Diane

is a member of the Seven Deadly Sins, titled the Sin of Envy, with the symbol of the Serpent. She is a member of the Giant's Clan, and is thus much larger than ordinary humans, including her fellow Deadly Sins. However, Diane left or was separated from the Giant's Clan when she was a child for unknown reasons.

Appearance
As a giant, Diane is several times larger than an ordinary human being. She is a fair maiden, possessing a pair of pink eyes and medium length brown hair which is tied up into large twin tails. She has a particularly well-developed and curvaceous body. Like most of the other Deadly Sins, her facial appearance is relatively childlike and has shown little change over the years. Her attire consists of a short-sleeved one piece orange suit, boots - with five crossed laces - that extend almost up to her knees, and two finger-less gauntlets of a blueish leathery material covered in shiny steel studs - her right one was destroyed by Gilthunder during the fight in the Forest of White Dreams and it has not yet been replaced. She also wears backpack previously used by Meliodas.

Ten years ago, Diane wore full body orange armor with a unique helmet like the rest of her fellow Deadly Sins. Her symbol, which is of the Serpent, is located on her left outer thigh. Diane's wanted poster depicts her with light colored hair. When she was still a child, she wore ragged clothing until King made her a new set. Her current clothes resembles what King made for her, having sewed it herself by using leather derived from Dusk Bison skin.

Personality
Diane is a very friendly woman, and is also very confident regarding her abilities, appearing to generally consider Holy Knights as weak. She cares very much about her captain and holds very strong feelings for Meliodas, often cuddling him to display the same, and becomes very delighted at compliments. Her feelings are strong enough for her to overcome her fears for his sake. However, she is very quick to throw temper tantrums, and often does so upon becoming upset.

Due to her size, she cannot help Meliodas in any way other than fight for him, she has expressed her strong desires to be smaller, contrary to Elizabeth's desires of being strong. Like Elizabeth, Diane does not mind when Meliodas does something perverted to her, but gets angry and jealous if he does it to others. Despite Diane stating that she has no interest in humans, she still selflessly saves people who are in danger - when the elderly man in Byzel and Zeal were at risk, Diane risked her life to protect.

Despite her brave and strong appearance, Diane is a somewhat emotionatlly fragile person, as displayed for her hatred of loneliness. This was shown when she was a child when was waiting in tears for King to return for her and insisted him to stay by her side when she was sick, instead of getting herbs to heal her. Diane possesses the same kind of feelings toward Elizabeth after she had been kidnapped by Helbram, wanting her back to not feel alone again.

History
Many years ago, after Diane had left or was separated from the Giant's Clan, she formed two rock-like golems to accompany her, despite either of them unable to talk. Diane found the injured King near by a lake and took care of him until he felt better. Over the period of hundreds of years, King ended up forgetting about his life as a Fairy King and spent his time playing and protecting Diane. Diane later met a old man, a human, who offered Diane and King some food despite being Fairy and a Giant. King was wary with the old man, and told Diane to be careful around humans. Due to unknown reasons, Diane ended up getting a fever, in which King panicked due to Fairies never having fevers and went out to get herbs. However, Diane stop him, telling him to not leave her side since she was always alone. The old man who gave them food found them, and concocted an herbal medicine for Diane's fever, eventually curing her of her ailment. As soon as Diane got better, King and Diane ended up playing tag with each other, as King told her that if she caught him, he will grant her a wish.

Diane took it seriously and caught King, but end up getting her clothes ripped off in the fray, leaving her entirely naked, much to King dismay. King end up making her new clothes and the two went to visit the old man hunter's place, only to find more houses had sprung up around there, and that the hunter had a grand child now. Years had passed by without King or Diana noticing. After leaving the forest, King told Diane about marriage between two humans who love each other. Diane asked if King loves her, which he flushed to, but agreed. Diane thus chose to use King's promise to make him always love her. He agreed wholeheartedly. Later that night, King ended up remembering who he is through various flashbacks in his dreams, and found out that the village close by is on fire. King told Diane to stay back as he went to the town. Diane waited in tears, hoping for King to return, only to find King return and strike her with a flower to her spine to make her forget who he is. Diane eventually awoke from her slumber without any memories, but curiously picked up King's flower and walked outside.

After hundreds of years later, Diane had grown into a women, and entered into a petty argument with a group of knights called the Knights of the Golden Wheats, who had discriminated against her for being a giant. Meliodas stopped them, then questioned Diane if she was frightened; his having treated her as he would, a normal girl of his size made her feel as though she was his size, i.e., small. At some point of time, Diane joined the Seven Deadly Sins, though her sin wasn't revealed yet. In a mission to wipe out a group of vampires, Diane and King were suddenly weakened due to a drunken Ban's deliberate use of Snatch and as a result, the two have had a hard time in battle. Diane did not knew of the cause until 10 years later when Gowther revealed that event. Before the betrayal, Diane and her fellow teammates met with King Liones and young Elizabeth, whom she did not remember until 10 years later when Gowther revealed it.

10 years ago
The Seven Deadly Sins, including Diane, were summoned to a castle to meet the Great Holy Knight some time after defeating the troll queen and, at the same time, destroyed the Great Druid Altar. On their way, Diane speculated that the Great Holy Knight might reward them in their last mission, though Merlin predicted that it'll be a scolding from their superior. When they find him dead, they are ambushed by all the Holy Knights in the kingdom, with Diane later being able to escape and reach the Forest of White Dreams, where she forced the indigenous Prankster Imps to hide her, lest she go on a rampage.

Introduction arc
Diane's wanted poster is displayed on a board within the Boar Hat.

Forest of White Dreams arc
The defeated Prankster Imps retreat to a sleeping Diane, inadvertently leading Meliodas, Elizabeth and Hawk to her. Diane wakes immediately upon hearing the Imps' apologies for allowing a Holy Knight come through, since they believed Meliodas to be one, and then instantly grabs Meliodas with a hand. After realizing his identity, however, she cuddles her captain, and when Elizabeth introduces herself to be traveling with him, throws a tantrum. Meliodas, after calming Diane, begins a discussion on the day the Deadly Sins were framed for the Great Holy Knight's murder. However, he also reveals that he has almost no memories of the day they, and then narrates the only memories he has, which end with someone apologizing to him, addressing him as "captain".

This leads Elizabeth to speculate the existence of a traitor, and Diane, to declare that she will help Meliodas no matter the foe. Few moments later, Hawk notices a gigantic thundercloud in the sky, from which a lightning bolt descends and immobilizes all of them, with Elizabeth introducing the assailant Holy Knight as Gilthunder. After he leads her away, ending her interruption, he expresses his desire to fight Meliodas, and reveals his connection to Zaratras, the Great Holy Knight. Before the battle, Meliodas and Diane easily break his immobilization themselves, and the former instructs the latter not to interfere. Diane quietly observes the battle, watching worriedly when Meliodas is gravely slashed. When Gilthunder continues attacking Meliodas and refuses to end the battle, Diane grabs him, and ignoring his attempts to escape her grip, flings him from the the forest. Sometime afterward, Diane leaves along with her captain, Hawk, and Elizabeth. Meliodas decides to head for Baste Dungeon, where Ban is imprisoned, leading Elizabeth to object, citing his grave wound at Gilthunder's hands. Though he affirms her that it is not major, he soon collapses.

Baste Dungeon arc
Diane, Elizabeth and Hawk then travel to a town near the Baste, named Dalmary, in order to have the severely injured Meliodas by Dana. As she sits next to Dana's house, she is watched with discriminatory wariness due to being a giant. Not longer, Diane decides to head to the dungeon herself, retorting that Elizabeth would be only a hindrance when the princess asks to join. Elizabeth replies her desire to be of use, and that Meliodas was taking on "more than he can handle". This angers Diane, her saying that Meliodas was not doing so for the princess alone, and that such was his usual personality. She continues, narrating the episode of her and her captain's first meeting, and how he treated her at that time. As Elizabeth declares her wishes of wanting to have strength, Diane declares her own of wanting to be small. Abruptly, Hawk notices a huge swarm of poisonous insects flying toward Dalmary.

Although initially plagued by her fear of insects, Diane overcomes it and quickly kills them by raising huge pillars from the earth, much to the surprise of Friesia, the assailant. While Elizabeth and Hawk awe at Diane's ability, and she leaps out of Dalmary and, handing Elizabeth the duty of taking care of Meliodas, starts running toward the Baste Dungeon. Diane, later on, encounters Meliodas, Elizabeth and Hawk when the three are walking to the Baste Dungeon. She mysteriously seems to have no recollection of having defeated Friesia and having left for the dungeon previously.

She tries to recollect, when she suddenly finds Meliodas and Elizabeth to have vanished, and Ruin to be standing in their place. When the Holy Knight claims to have already captured them, she attacks him, but is soon revealed to be under an illusion that deludes her into seeing Ruin in Meliodas' place; she thus attacks Meliodas while believing that she is attacking the Holy Knight. Meliodas, immediately flees along with Elizabeth, and Hawk, and upon finding two civilians walking nearby, takes them along. As the five hide, Meliodas also falls under Ruin's hypnosis. Seeing Ruin in Diane's place, he, thinking he is attacking Ruin, jumps up, rolls and slashes from above, with Diane blocking it with her fist and responding by raising sharp pillars from the earth toward him, with he in response deflects. Diane and Meliodas' battle continues, uninterrupted, and only stops when Elizabeth manages to remove the source of Ruin's illusions - his staff's bell.

Later, during the aftermath of Meliodas and Ruin's battle that ends in the latter's defeat, Diane quickly defeats Friesia with a punch that utterly crushes the Holy Knight. Walking towards the heavily injured Elizabeth, Diane removes her giant backpack, intending to place her inside and take her to the town for treatment. Elizabeth, however, requests to be taken inside Baste, to which Diane complies. The second, and older shepherd is revealed to be a soldier who was ordered to act as a civilian. When he refuses to reveal Ban's location due to fear of his superiors, Diane threatens him while holding Friesia's defeated body. Inside, the group encounters Cenette and Ban. As Meliodas and Ban greet each other, and arm wrestle, thus destroying the entirety of Baste, Diane simply watches as though this was a common occurrence. The group, along with Cenette and the other villagers, return to Dalmary where Diane looks after Elizabeth.

At night, during the party, Ban is formally introduced to Elizabeth; Diane has to stand while eating due to her size. During the party, Elizabeth expresses her joy, but states that the events in Baste have reminded her all the more about the Holy Knights' frightening abilities. Diane replies that while she is not interested in human kingdoms, she has no qualms with fighting for Elizabeth, since she was "really cool" that day, and did have powers: the power to move her and Meliodas' hearts. Diane also asks Elizabeth whether she could henceforth address her as merely "Elizabeth", instead of "princess", and then tells the young lady to address her as just "Diane".

Capital of the Dead arc
Diane and the others left Dalmary Town to travel on the road again to find the other Sins. When Elizabeth apologizes to her for making them wait when she needed to heal but Diane said she shouldn't worry too much. When Meliodas was about to say when they should be going a group of two apprentice Holy Knight who want to know where are they going and who are they because of Hawk mother and Diane being from the Giant Clan. Meliodas came out and told them that they are a traveling bar and that Diane and Elizabeth were they attractive waitress. The plan was working until Diane hugged Meliodas and call him captain because she was happy being called attractive.

When the apprentice Holy Knight was about to attack a Black Hound attack and killed them! Meliodas scared it away by using his power and they continued on they traveling. Meliodas told them that they are going to the Capital of the Dead to find King. When they got to a village next to the Capital of the Dead, they decided to find information to find King or how to get to the Capital. Meliodas pick Diane to be a attractive waitress to bring in costumes which she was happy and Ban as the cook. Diane was standing outside all day to call people in but nobody came because the villages was empty? The Sins realize that Ban left before starting business and decided to go out and find him. When they found Ban fighting someone, Meliodas stopped him and show who it is, both Meliodas and Diane recognize that person is King much to Ban shock. Diane went to him and told him that they been looking for him but King turn the other way and left. Diane and the others went back to the Boar Hat and were serving food to a local girl named Ellen and her brother.

They got a information that King wanted to go to the Capital of the Dead and told them how do get there.When they left Diane was wondering why King left. When they got there the flowers around them started to move and made a wind which send them to the Capital of the Dead. Ban left the group to follow something and they saw King was following him too? When they were trying to find them, a Holy Knight appear to them and her named was Guila and she said she killed herself to get here. Meliodas sense how dangerous she is and told Elizabeth and Hawk to leave. Guila launches an attack that and sends the two Sins flying, but Meliodas manages to catch Meliodas before she fell on a sharp crystal.

Guila then comments that the capabilities of the Giant Clan and Diane's ability, "Creation", are not very impressive. As a response, Diane demonstrates her abilities by using hand seal signs and made her move Sand Whirl and trap Guila in it but Guila easily frees herself with a blast from the tip of her rapier. She forces Diane back with another explosion but later she came back and try to crush her but she dodges it with ease and explodes her again. But when seem at last Ban came back and used his ability Snatch but she got herself freed by using her power Explosion. The rest try to fight Guila together but she was too powerful and when Guila explosion Meliodas, Diane came in the right time and saved him much to her joy of how she saved him.

Diane was now blocking all of Guila attacks and now Diane is heavily wounded and couldn't move. But then King came in and told them that he is here to help them. Guila then sent a multiple of attacks toward them but King easily block them all with his spear. Guila comment on his spear power and wanted to fight all the Sins but King said he wanted to fight one on one with her only and told the other to rest now. After King defeated Guila, the rest of the Sins bodies were disappearing because the Capital of the Dead is rejecting them and are about to go back to the living world. When they got back they saw that Guila was there by still in near death and Meliodas offers to do something to her. Later the Sins stop to rest somewhere and Diane was better now.

King was worry that Diane might still be injury from before and told her to rest but Ban told him that she might have faked it, so that Meliodas might pay attention to her much to King angry. Elizabeth comment at King how strong he was which got King thinking and told the Sins that they could have beaten Guila with ease like him with they sacred treasures and told them what happen to them. To King shock he found out that the other Sins no longer has them, Diane lost hers somehow. King was now yelling at Meliodas and Ban for not having these but when he saw Diane doing a sad cute look, King told her she lost it and nothing can be help.

Byzel Fight Festival arc
The next day, Diane is left behind at the Boar Hat while King, Meliodas, Diane and Hawk travel to Biron, since she is easily noticeable. The next day, Diane throws a tantrum at similarly not being able to accompany them into Byzel, when Elizabeth offers to join Diane. The two then head into the forest to gather ingredients for dinner. In the woods, Elizabeth finds a mushroom-like monster, which Diane, tries to grab, considering it an ingredient. The creature, much to Diane and Elizabeth's shock, releases spores that shrink both of them. The latter wears the former's clothes and jewelry, in order for them to not be lost, and then, wanting to surprise Meliodas, enters the Byzel Fight Festival under the name of "Matrona", with the shrunken Elizabeth hiding in the shrunken Diane's bosom.

As Matrona
The shrunken Diane is first seen during the preliminary of the fighting festival, in which, she quickly and easily defeats many of the other contenders, and advances. Afterwards, she is assigned to fight against Griamor. After she, and her opponent, have entered the ring, Love Helm, the referee, requests her to remove her cape to confirm whether she has any weapons. She does so, revealing her incredible identicalness to Elizabeth. Griamor, dismissing Veronica's worries about "Matrona" being Elizabeth, readies himself. As the battle begins, Diane immediately attacks Griamor, all of which are, negated by the Holy Knight's ability, "Wall". While Diane is being pushed outside the ring, Griamor states his intentions humiliating Meliodas next. This enrages Diane, who proceeds to destroy Griamor's ability, and then defeat him, both with a single punch. This greatly surprises both Veronica and Hauser, and causing Diane's hat to fall off.

As "Matrona" is declared the victor, and her facial appearance is now revealed to be identical to Diane's, she skips towards Meliodas, Ban and King, believing that her secret has been revealed, but is only greeted with Meliodas' question as to her identity. Irritated, Diane punches him storms off, turning back when King asks her about her body, and Elizabeth's whereabouts. Diane replies that "she" is right there, with an expression of Elizabeth's. After Elizabeth appears from Diane's bosom, Diane, explains how she and the princess shrunk, upon hearing which King recognizes the creature that did so. Diane jumps over Meliodas, merrily expressing her elation at being held by him. She then asks Meliodas to grope her all over the body, as how he often gropes Elizabeth. When Diane becomes upset at his refusals, Meliodas comforts her, explaining that he cannot act so to an important individual as her.

Diane then watches Cain and King's, and then, Meliodas and Ban's battles. During the latter battle, when Meliodas appears to be weakening, Diane wonders the reason, which King answers as being due to Ban's ability, Snatch. After Ban completely steals all of Meliodas' abilities, and stands over him, Diane yells at Ban to not further harm Meliodas. Meliodas himself refuses to give up, leading Diane to theorize that Meliodas is baiting Ban to delivering a powerful punch, and will then reflect it with Full Counter. King, however, explains of Full Counter's limits, that doing so would be impossible. After Meliodas somehow wins, Diane tells King him that in midst of Ban's attack's aftermath, Meliodas' eyes suddenly became black, and that he had a strange symbol on his forehead; she states that Meliodas then crushed Ban's hand, then going on to defeat him. Diane states that she has seen this before, and that it makes her feel uneasy. When the next battle is declared to be between "Matrona" and Hauser, Diane hurriedly hands Meliodas a shrunken Elizabeth and the princess' pendant, before leaving for the battle.

As the battle begins, Hauser informs Diane that her chest button was undone. After the minor resulting interruption, he charges, attacking with a small tornado around his arms. Diane, while dodging, comments on the attack's danger. After much evading, Hauser, finally, proceeds to deal the final attack, but finds "Matrona" to be easily stopping him. Diane pushes him away with a single slap, adding that she had earlier commented his ability to be dangerous, since she did not want her clothes to be torn. Finally able to unleash his powers, Hauser uses another technique, which causes Diane no damage again, leading to Hauser's confirmation that she is a Deadly Sin. Not giving up, he then forms a gigantic twister, large enough to cover the entire ring. Despite his confidence of his victory, Diane increases her body's mass, and uses the increased gravitational force to defeat Hauser from above. Hauser then acknowledges his defeat and states that he is honored to have been fought seriously by Deadly Sin; he then confirms Diane's identity when King addresses her by her name.

During Cain and Meliodas' battle, when Diane wonders about the fighters' relationship, Ban instructs them to stop, citing the third law of the Deadly Sins. After the battle, the final battle of the Fight Festival, between Meliodaz and Matrona is announced. Just as Diane suggests to merely act as if they are fighting, three women cheer Meliodas in an erotic manner. Diane, enraged, assumes that Meliodas' obliviousness is since he has relations with so many women that he doesn't recognize them all, and, enraged, punches him to the ground.

Diane refuses to believe Meliodas' claims that it was a misunderstanding, and exchanges a barrage of very powerful and relentless attacks. As Meliodas attacks, he wonders why she is as powerful even after shrinking. He then jumps, and tries to land the finishing blow. His punch is, however, stopped by Diane with one of her own. As she pushes Meliodas back, her size gradually returns to normalcy. Diane continues attacking Meliodas, but he repeatedly evades her by slipping through the cracks on the ring. When the audience expresses its dislike at the low seriousness of the battle, Meliodas declares his identity, and that he will now be taking over Byzel. Ban and King also enter the ring, with Meliodas continuing that he will give the town a chance: he orders then to leave Byzel, lest be massacred by the Sins. A few moments later, several gigantic flares rain down on the town. The attackers are shown to be Guila, Jericho, and another Holy Knight; the citizens, believing that the three have come to save them, cheer, but are quickly threatened into fleeing.

As Diane
Elizabeth then understands the Sins' actions: they acted so in order to have the civilians evacuate. Meliodas notes that their opponents are much more powerful than earlier, and instructs King, Diane and Ban to separate. Diane, acting upon her instruction, then reaches the area where Gideon was kept, but finds the weapon to not be there. As she wonders on her course of action, Hauser walks up from behind, declaring that he will be arresting her, since he believes that they are plotting to take over the kingdom again. Diane then notices a civilian trapped under the debris and runs to his help, just as Marmas also walks up to the two, and proceeds to use a technique that multiples gravity around Diane by ten times. Diane throws the civilian to Hauser, as the earth collapses due to her increased weight.

After being dropped into the pit, Hawk's Mother appears before Hauser and Marmas, carrying Diane's original clothes and tosses them into the large opening. After Helbram successfully defeats the rampaging Meliodas with a portion Hendricksen's powers, Diane appears from the hole, smashing Marmas at the same time. As Diane climb out of the pit, Diane ask Hauser if he is surprised that Diane true size, but Hauser told her he was not and was glad she was okay.Diane then ask Hauser to take Marmas and the old man, and ran away which surprised Hauser, Diane then ask if Hauser will try to capture her, but Hauser told her that the Kingdom will be after them because of what happen to Byzel, but Hauser doesn't understand what to think of it. Diane later found her sacred treasure Gideon and headed toward Meliodas and Helbram fighting area where she saved him before Helbram could take him away. Diane saw the defeated Meliodas and she went into a deep thought until she went furious at Helbram for what he done to Meliodas and use Gideon to crash the area around her.

Helbram started to retreat due to Diane great powers and Hendricksen order him to escape, but Diane then form a giant floating mountain and crush Byzel, possible killing Helbram. Later when the smoke clear up, Diane look at the injury Meliodas which he woke up and saw Diane, Diane then got so happy to save Meliodas and cuddle him. As Elizabeth was running toward the injury Meliodas, he was then punch by Ban who was angry at him for cutting him in half which made Diane upset at Ban. Diane later pick up Meliodas and was upset at him because he told Elizabeth that if she is alright, then he is happy to which Meliodas calm her down saying she is always fine. Later Diane thanks Hawk Mother for getting her clothes and headed with the rest to a new location to find the other Deadly Sins or the next sacred treasure.

Armor Giant arc
After the Boar Hat stop at a unknown location, Diane found Elizabeth saying she will return the kingdom back to the way it was. Diane told her she shouldn't worry about it and she is free to use their powers since they are comrades. Diane and Elizabeth later met up with Ban and King who went to see Meliodas who they were shock to see the slice up mountain cause by Meliodas. Later, a group of kids who are role playing as the Deadly Sins, found there bar and questioning them, Diane, who was hiding behind, thought everyone came back, and appear to the kids who were shock to see Diane, thinking she going to eat them which got her angry, saying she doesn't eat people.

After the all thing clear up, Diane end up playing with the kids, in joy. Pelio then told them about a Mountain God who lives in Ordan mountain. Then they were later informant from a villager that a group of Holy Knights Dawn Roar and the kids headed to the forest to find them. The Deadly Sins then hear from a unbeaten knight that a "Armor Giant" was at the mountain and beaten them all with ease. Meliodas then realize it was Gowther. Once Meliodas explain the situation to Diane, the latter than realize that Gowther was pretty big and wearing armor. Diane ask that she can go, but Meliodas refuse and order her to stay behind and protect the sick Elizabeth.

Diane was surprised but happily agree stay behind. Diane was later inform from Hawk that Cain Barzad came to the boar while he called him names which Diane told the latter it was rude. When Cain ran out of the bar to see what's happening in the forest, Cain was surprised to see a giant in the area and wonder how she knows him. The Deadly Sins then return with Gowther where Diane and Elizabeth were surprise to see Gowther without his armor, but all of them end up celebrating. Gowther later used his power Invasion on Diane and Ban which he revealed that Diane was lying about her true height which she is 30 feet tall not 29 to her embarrassment and smash him to the ground repeatedly. When Gowther revealed that Elizabeth is in love and it could be Meliodas, King and Ban try to calm Diane down but were surprised to see her pass out due to drinking.

Kingdom Infiltration arc
Diane was chatting with Hawk's Mother about what she eat which Diane doesn't understand the latter language and got mad when Meliodas needed comfort from Elizabeth as she break the window. As Meliodas explain his reason to head to Liones and get his sword back, Diane wonder why if the Demons are release yet, Meliodas reveal that their are more pieces to the Eternal Darkness since the seal is incredibly strong and there would have been a sign. Hawk ask why the Holy Knight are after Elizabeth as well, until a mysterious Holy Knight appears and reveal that Elizabeth is the last key needed to revive the Demon Clan. The mysterious Holy Knight took Elizabeth and Meliodas order Diane to toss him to Liones along with Ban and Gowther. Diane grab hold of the Deadly Sins as she told Meliodas to bring back Elizabeth, and toss them toward Liones in full speed.

Diane and King start travelling to Liones by foot along with Hawk's Mother, planning to help out as they are the ones two possessing Sacred Treasures. She asks King if he had ever seen Meliodas so angry before and King replies that it was his first time seeing him like that. Diane begin wondering if she had been kidnapped instead of Elizabeth, would Meliodas be as anger for her. King tells her that Meliodas will definitely go to save her since they are important friends, and states that he himself will definitely come for her. Diane tells him that she is happy, but King wonders she is actually cheered up. He soon realizes that they should hurry and summon his pet, Oslo. He reveals its ability of teleportation and tells Diane to enter Oslo's mouth. They eventually realize that she is too big for the Black Hound's mouth, so Diane tells him to push her in. King blushes at the sight of her rear end and quickly orders Oslo to open his mouth wider.

Diane arrives at Hendricksen's magical research building, and is immediately questioned by Dreyfus, asking for her goal. Without hesitating, the Deadly Sin demands to have Elizabeth returned, leaving the Great Holy Knight only confused. Hauser becomes more and more nervous, and Jericho decides to deliver the first attack. Diane straightaway swings Gideon, destroying part of the building and blasting Jericho away. Gilthunder then proceeds to begin attacking, and under Dreyfus' commands, Hauser reluctantly enters the battle as well. However, despite using a combined technique, Diane was able to fend off the technique by using Ground Glagius. When she attempts to unleash Ground Glagius for a second time, Dreyfus easily blocks it and uses his ability Break to pierce through her chest.

After being heavily damaged by Dreyfus' Break ability, Diane briefly collapses on the floor whilst coughing out blood. Helbram returns to the group of Holy Knights after evading Diane's Ground Glagius by sacrificing some of his subordinates. Diane attempts to move again, but Dreyfus uses Pierce to damages her leg, and is sent flying away to the city by the Great Holy Knight's technique, Pulverize. When she crashes into the buildings and astonishes the civilians, Dreyfus proceeds to use an Incantation Orb to project his voice throughout the kingdom, stating that the Seven Deadly Sins have infiltrated Liones to stage an attack. The civilians begin attacking and throwing rocks at the confused Diane who tries to explain to the people. Helbram proceeds to destroy more buildings to frame Diane as a villains. Guila notices the trickery and demands Helbram to explain his actions, which he replies by saying that the Sins will play the role of villains so that the Holy Knights can be heroes. Suddenly, Zeal notices Guila, when a building starts collapsing above. Without thinking, Diane leaps and dives forward to protect Zeal, causing herself to be completely immobilized by the collapsed building. As the Holy Knights prepare to kill her, Hauser and Guila steps in to protect Diane.

As Guila and Hauser initiated a suicidal battle against their former comrades, Diane tells Zeal to stay down while she protects him from the destruction caused by the two rogue Holy Knights' Combined Technique: Bomb Cyclone. As Dreyfus and Gilthunder left the battle field due to Dreyfus injury. Helbram was left behind to finish them off which he called upon Call of Inferno which nearly killed Hauser and Guila until Diane stood up and smash Helbram before he could do anymore damage. Diane give Zeal back to Guila and told them to get to safety, but Hauser refuse, saying that she should worry about herself than others for once which she smile. But Helbram raise up and strike Diane with Killer Iceberg that heavily damage Diane even further and put her to a near death situation. Helbram unleash many ices to finish her off until King appear and start all the attacks to save Diane. As King trying to find the one who injury Diane, Diane told King it wasn't Guila or Hauser as their try to save her until she passed out.

As King protected her from Helbram roots attack, Diane woke up a little to smell King as she say she remember the smell and say King true name, Harlequin as she shed tears. After Helbram was killed by King, King flow toward the injury Diane and apologize to her for getting her in trouble, but Diane instead thanks him for saving her. King told Diane to leave everything to him, but Diane then said Harlequin which surprise King until Diane said that name sound nostalgic to her, but doesn't know why. King smile and said it could have been a dream. Diane later start forcefully getting up while King try to convince her to rest due to her injuries, but Diane refuse as Elizabeth needed to be saved and King pollen heal her. While the others were trying to get Dreyfus on there side to save Elizabeth, Diane told Dreyfus she did not care if Dreyfus hurt her, but wanted to save Elizabeth as she was a important friend to her. As everyone got ready, they headed out to Hendricksen location to save Elizabeth.

While on their way to save Elizabeth, Diane and the Sins feel a large amount of power exerted with very strong force in a nearby battle. After Gowther explains that Meliodas is fighting three Great Holy Knights, Diane begs King to go and help Meliodas, but King refuses as he wants to remains near Diane since she is still injured and knows that Meliodas is fine on his own. As everyone senses Gilthunder's full power, King realizes the fighting has stopped. Diane screams, thinking that Meliodas was killed, but Gilthunder, Margaret and Meliodas show up, revealed to be fine. Diane begins to cry and holds Meliodas, which Meliodas ignores and tells the group that they need to rescue Elizabeth. The group heads to the castle to rescue Bartra and Elizabeth, but are teleported to a forest by Vivian. Fortunately, they are sent back to Liones by Arthur's mysterious cloaked figure, who is soon revealed to be Merlin of the Seven Deadly Sins.

Abilities/Equipment
Diane is shown to be incredibly strong. She was able to punch the ground and use the ground to stop a horde of bugs from destroying a town. She has also shown to have great endurance as she was able to resist Gilthunder's lightning and even break free from it. As Matrona (normal human size), she possesses incredible physical strength and speed which she displayed during the fighting festival's preliminaries by defeating more than ten men quickly and with ease. Even as a young child, Diane demonstrates extraordinary connections with nature, being able to create two Golems.

Gideon
Diane's sacred treasure; Gideon, is a war hammer designed for the Giants' Clan. It is made of material that is stronger than steel and weighs approximately 2200 pounds. It is able to draw out the full capability of her ability, Creation.

Abilities

 * Creation: This ability, which is exclusive to members of the Giant Clan who have a deep connection with nature, enables Diane to manipulate the earth.

Meliodas
Diane and Meliodas are both members of the Seven Deadly Sins. She is madly in love with Meliodas for treating her like a normal size girl, so much that she immediately desired to fornicate with him after shrinking in size. She often gets very jealous and hits him for being close to other women. Her future dream is to become little and have children with Meliodas  She respects him a lot and calls him captain.

Ban
Diane and Ban are both members of the Seven Deadly Sins. They are fairly friendly with each other, but as always, the only man Diane cares about is Meliodas.

King
Diane and King are both members of the Seven Deadly Sins. When they first met after ten years, she was happy to see him again and she might not realize that King is in love with her. When Diane was a child, she extremely close to King, and told him to always love her. However, her memories were sadly erased, causing her to forget her time with King.

Gowther
Diane and Gowther are both members of the Seven Deadly Sins. They are fairly friendly with each other, but as always, the only man Diane cares about is Meliodas.

Elizabeth
At the beginning, Diane dislikes Elizabeth as she is jealous of her close relationship with Meliodas. She envies her small stature and her abilities to be able to take care of Meliodas when he is sick or ill. However, after seeing how courageous and brave Elizabeth was when she was willing to sacrifice herself for innocent citizens, they developed a closer relationship and Diane acknowledges her, even stating that she doesn't mind fighting for her. Diane later grew to care for Elizabeth as a dear friend, as she was worried about her when she was kidnapped and even fought a Great Holy Knight just to get her back.

Baste Dungeon Arc

 * Diane vs. Friesia: Win
 * Meliodas vs. Diane: Indecisive

Capital of the Dead Arc

 * Meliodas, Diane & Ban vs. Guila: Indecisive

Byzel Fight Festival arc

 * Griamor vs. Matrona (Diane): Win
 * Matrona (Diane) vs. Hauser: Win
 * Meliodaz vs. Matrona (Diane): Draw, interrupted
 * Diane vs. Helbram: Win

Kingdom Infiltration arc

 * Diane vs. Dreyfus, Gilthunder, Hauser, & Helbram: Lose

Trivia

 * Diane is a very common given name, and the Roman name of the Ancient Greek deity, Artemis.
 * She relishes whole roasted pigs.
 * She has known an individual by the name of "Matrona", whose name she used to enter the Byzel Fight Festival.
 * Diane is entomophobic, i.e., has a fear of insects.
 * Diane told everyone that she is 29 feet tall, but Gowther pointed out that she is actually 30 feet in height.
 * Due to her immense physical size, Diane is unable to sleep inside the Boar Hat, so she sleeps outside.
 * Diane tends to cover her face with her hair whenever she is embarrassed or shy.
 * Diane current outfit was made by King, using a tanned hide of a Dusk Bison.

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Diane