Merlin「マーリン」 is the Boar's Sin of Gluttony of the Seven Deadly Sins. She is regarded as the greatest mage in Britannia. Her Sacred Treasure is the Morning Star Aldan, a floating orb she can summon at will and often uses in conjunction with her spells and her inherent power Infinity. The name "Merlin" is actually an alias as her true name is unpronounceable to humans.
Ten years afterwards, Merlin was first seen wearing a long violet cloak that covered her whole body and her face, making her sex ambiguous. When the cloak was ripped apart, Merlin was shown to look very similar to her appearance on her wanted poster. She is seen as a slim, attractive, tall woman with three beauty marks below her right eye (though after her reappearance after Hendrickson's defeat, she appears to only have a single, lower-placed, larger beauty mark). Her outfit consists of a highly revealing and open fur collared long coat, with heart shaped buttons, short shorts that resemble panties with a heart on it, and thigh high boots. Merlin's hair is at shoulder length and black.
After having her magic seal spell reflected back by Chandler's Full Counter, it is revealed that her true form is that of a child. In this form, she is described as an adorable child by Chandler with long black hair reaching her mid-back.
At the end of the Demon King arc, Merlin was left with burns around her chin and mouth. She herself decides to keep the burns as a symbol of Escanor's existence after he died.
Prior to the Seven Deadly Sins' supposed betrayal, Merlin demonstrates a playful nature telling her teammates that their meeting with the Great Holy Knight might turn out to be a scolding from their superior for destroying the Great Druid Altar. Merlin is also apologetic in asking for her captain's forgiveness for knocking him out. She enjoys mocking and challenging others, teasing her apprentice Vivian for losing herself in rage again. Merlin tends to use anyone as a magical guinea pig to test out new techniques she learned so long as the results are good (as Meliodas had noted).
Merlin is a very calm and passive woman almost never losing her cool regardless of the situation. Even as she and everyone were being overwhelmed by Galand, Merlin remained calm and was able to think of a strategy to counter him. The only time she loses her calmness is when the situation is beyond her ability to cope such as Meliodas reverting to his previous self or when Arthur was impaled by his own sword.
Merlin is described as a very mysterious woman as many who know her have a difficult time telling what she is after. She expressed excitement when the Ten Commandments were free, primarily knowing she could gain a large amount of information from their appearance and taking an interest in Escanor's powers due to the many mysteries surrounding him. According to Meliodas, Merlin tends to take an interest in anything that is considered "rare" such as Escanor's powers and various Demons she can use for her experiments. Even Demons have a hard time understanding what she's after.
Despite her mysterious nature, according to Escanor, Merlin is a very kind and cheerful woman. She is normally kind and polite to everyone around her, even those she does not know. Merlin is also the only person who treats Escanor as a person rather than a monster as everyone else does prior to him joining the Sins. She also has a motherly side, treating Arthur as a mother would a son and was deeply saddened over his death.
Despite her usually kind and calm behavior, Merlin knows when to be serious. As when regarding the revival of the Commandments, she scolded Hawk for taking the situation lightly. She also took command after Arthur was killed refusing to let anyone else she cares for to die.
Merlin loves knowledge above all else. Because of her desire to learn everything, she suspended her own age to have all the time in the world to study and learn everything. For that reason she regularly takes excitement whenever she has the potential to learn anything she does not know about. She was interested in Escanor primarily due to his unique powers as well as how it fluctuates during the day and studies a captured Grayroad to learn more about how his Commandment works. Because of her desire for knowledge, Merlin is a very shrewd and intelligent woman being able to calmly assess the situation at hand no matter how dire it is as well as explaining the mechanics over any form of creature or magic by heart. However, Merlin is not above acknowledging when she does not know something or when a situation is beyond her capability to understand.
Despite Merlin being usually calm and serious, she is capable of being shocked or embarrassed. As when Elizabeth regained her memories she asked Merlin if she could call her "Big Sis-Sis" like she used to which left Merlin deeply embarrassed. She even was embarrassed when the others Sins (mainly Escanor) asked if Elizabeth could talk about it more.
She appears to have very little modesty, as Merlin has no problems wearing very little in public or even allowing Escanor to give her a massage while she was taking a bath.
3,000 years ago
Merlin was born in Belialuin, the capital of the wizards, which remained neutral in the conflict between the Goddess Clan and the Demon Clan. She was taken on the path of wizardy by her father and the magician Gowther. Merlin was born with the strongest and most unique magic, besides being a prodigy with a talent and wit such that she surpassed the wisemen of the capital. Together with other children with aptitude for magic, Merlin was experimented on by the people of Belialiun as a test subject under the pretext of researching the ultimate magic, but in reality they sought to turn the children into weapons against the higher ranking goddesses and demons.
Deep down, Merlin was a child hungry for the love of a parent. However, her father, the chief sage of Belialuin, never gave anything to her other than study material and tests to carry out. One day, sick of that life that she felt like prison, Merlin fled Belialuin. The people of the capital went after her, but Merlin managed to evade them until they eventually reached her. However, Merlin was saved by a member of the Demon Clan, Meliodas. When Meliodas put his hand out gently, Merlin's heart was filled with a love she had never received from anyone else. Over time, that feeling deepened until it became something special. However, no matter how much time he spent, Meliodas never showed romantic feelings for Merlin. Merlin then decided to abandon her form as a little girl and recreated herself in the image of an adult woman and stopped the time that coursed through her, hoping to win Meliodas's heart forever. Unfortunately, this hope was never realized because Meliodas fell in love with a goddess named Elizabeth. At first, Merlin was filled with anger, sadness and jealousy. Nevertheless, Merlin could never hate either of them. She even becomed very close to Elizabeth and considered her like a sister.
Merlin decided to return to Belialuin by her own foot and tried to fill the void that had remained in her heart, applying to the magical training, reading all the writings she could and greedily devouring all the knowledge of the world. However, none of this filled her and she spent her days tormented, until one day she listened to the wisemen gossiping and learned about a being called Chaos, the power drive born in the distant stars and believed to have created the world, as well as the Demon King, the Supreme Deity and the Sacred Tree, along with the Giant Clan and finally the humans; until it was sealed away by the two gods he had created. After discovering this, Merlin dedicated her life to resuscitating Chaos in the hope that this being who give rise to an unlimited unknown could finally satiate her starving heart.
When the news about a miraculous child born with infinite magic soon spread in the realms of the goddesses and the demons, both parties tried to put the girl on their side to tip the balance of the war in their favor. The people of Belialuin opposed this, claiming that both the girl and her power were their property. However, against the wishes of her people, Merlin decided to negotiate with the gods of both clans, the Supreme Deity and the Demon King, and said she would follow the one who gave her the best blessing. The Demon King gave her all the knowledge of the dark secret arts of Demon Realm and made her immune to the brainwashing and possession abilities of the goddesses. The Supreme Deity gave her protection against dark curses and Commandments. Merlin somehow managed to deceive both gods to renege on them by accepting both blessings. Furious, the two gods unleashed their anger against Belialuin, cursing it with fog and death for a thousand days and destroying it with fire and lightning. Merlin was able to escape unharmed, becoming the only survivor of Belialuin.
16 years ago
When Meliodas was serving as a Holy Knight in Danafor, he had an encounter with Merlin hoping that she could give him a way to break the curse that had been put on Elizabeth. Merlin suggests that if he recreates the Coffin of Eternal Darkness and releases the Ten Commandments, he could use the power that Zeldris borrowed from the Demon King to break the curse. Meliodas refuses to do so because of the danger he would represent and knowing that Zeldris would never help him, so Merlin agrees to look for another way.
Merlin would reunite with Meliodas when he was already serving the kingdom of Liones, as the founding members of the Seven Deadly Sins, and it was she who guided by the vision of King Bartra, identified the other five members, while Meliodas himself recruited them. While Meliodas recruited most of the Sins personally, it has been implied that Merlin helped somewhat with the recruitment of Gowther as Meliodas was friends with the original Gowther 3,000 years ago and both were aware of his past. At some point, Merlin gave Gowther an enchanted armor to keep him in check.
15 years ago
When Merlin and Meliodas met Escanor, they invited him to join the Seven Deadly Sins. However, the two were forced to restrain him by order of the King to stop the havoc that Escanor was causing in the villages, leading him to become a member of the Sins after Meliodas got the kingdom to exonerate him. The sorceress took interest in the man, and he fell in love with her at first sight. She was never afraid of his monstrous strength. Merlin witnessed the fight that Escanor and Meliodas had to decide whether Escanor would join them or not. After Escanor falls unconscious, Merlin fulfilled his request to reunite him with Rosa, sending him briefly to the Capital of the Dead.
It is known that Merlin participated in missions that the Seven Deadly Sins were assigned to. At some point in time, Merlin and her fellow Sins met with King Liones (who was accompanied by a young Elizabeth) according to Gowther.
12 years ago
Merlin and her fellow Deadly Sins were summoned by the Great Holy Knight Zaratras to discuss the recent loss of the Kingdom of Edinburgh to a clan of Vampires. Merlin did not fight much during the mission, simply teleporting the group to the location and keeping an eye on Escanor to ensure he did not lose control of his powers. After picking up Orlondi's eye ball, because Ban was tired from doing a hundred thousand push-ups, Merlin and Gowther were left to knock Escanor out and take him home after he killed the Vampire King Izraf. They then witnessed Meliodas' hidden power when he created a hole 30,000 feet deep. Later, she entered Escanor's room asking him to read a poem he wrote for her.
10 years ago
Merlin once took in Vivian as her apprentice in the arts of magic. She had to constantly remind her to end the habit of losing herself in rage.
After defeating a troll queen and accidentally destroying the Great Druid Altar, Merlin was summoned along with the rest of the Seven Deadly Sins to a castle to meet the Great Holy Knight Zaratras. After they found him dead, all the Sins were ambushed by the Liones Holy Knights. After Meliodas ordered the group to disperse, a little girl helped the Deadly Sins to escape. In the chaos, the girl was heavily injured, and Meliodas lost control of his anger. Merlin apologized to him and knocked him unconscious, stealing his strength and taking it to Istar to seal it away until the time came.
Abilities and Equipment
As a member of the Seven Deadly Sins, Merlin is very powerful. She is said to be the greatest magician in all of Britannia, and upon her introduction, she was capable of easily defeating some of the greatest Holy Knights in Liones and overpowers her former student Vivian, the most prominent mage of Liones. After freeing herself from Galand's petrification, she defeated Grayroad, one of the Ten Commandments. During the battle of Camelot, she singlehandedly defeats the two highest-ranked demons, Chandler and Cusack, who praise her as the "genius child" who deceived the Demon King and Supreme Deity. Ludociel, leader of the Four Archangels, states that he never wants to make an enemy of Merlin.
Merlin was born with a prodigious talent and wit that even during her childhood, she was able to overcome the wisemen of Belialuin. The simple mention of her birthplace and her true name is enough to frighten two members of the Ten Commandments and sends one of them fleeing for their life. Later Zeldris praises her for being able to escape from his attack and noted it was no surprise that Grayroad would lose to her. Meliodas later claimed that she only fell victim to the attack due to being "caught off guard" in a trance state.
Through her vast knowledge of magic and spells, Merlin has demonstrated the ability to levitate and is able to cast illusions, having produced a large powerful mirage army that tricked even the Great Holy Knights. Though Merlin is unable to use true healing magic like the Druids from the eastern forest, she is able to cure illnesses using her magic item Cure Angel. In the aftermath of the battle with the Ten Commandments at Liones, Merlin restored the battle-ravaged kingdom to its former state within a single night.
In battle, Merlin often opts to teleport her opponents into a multitude of harsh environments as she attempted against Vivian and Galand. She is also capable of creating magical portals into different spaces, as she did during the Seven Deadly Sins' invasion of Edinburgh. She can switch into multiple offensive spells which she channels through the sacred treasure Aldan. When battling against Grayroad, and Melascula's resurrected skeletons, she employed spells such as Exterminate Ray and potent magical blasts to incinerate her opponents. She also has access to an array of elemental spells such as Endless Whirl and Icicle Castle to overwhelm opponents, the former having enough power to destroy the castle of Liones.
In conjunction with her magic Infinity, Merlin utilizes an array of spells to serve supplementary purposes such as inhibiting the growth of Grayroad's demon eggs by freezing them for eternity and freezing her own time to create a form of immortality. She is also capable of using Infinity to vastly increase the potency of her attack magic, allowing her to overpower Chandler's enormous Exterminate Ray in his true form.
After receiving the blessings of both the Demon King and the Supreme Deity, Merlin gained immunity to the brainwashing and possession abilities of the Goddess Clan, as well as a strengthening of her spirit, rendering attacks such as Cusack's Resonant useless and resistance against magic attacks and dark curses, including the Commandments, as she was capable of freeing herself from the "Truth" commandment and remained unaffected by Grayroad's "Pacifism." Through the blessing of the Demon King and studies under the Ten Commandments' Gowther, Merlin has also gained knowledge of the secret techniques originating from the Demon Realm such as Perfect Cube and Absolute Order.
Merlin's greatest asset in battle lies in her knowledge and intelligence, using strategies to render her opponents helpless without engaging them directly, illustrated through her regular strategy of knocking Escanor unconscious through a combination of Power Amplify and Gowther's Blackout Arrow; her use of Perfect Cube to quarantine Meliodas, and her attempt to use Magic Seal against Chandler. The greatest example of this lies in her battle against Chandler and Cusack, where she utilized a thorough strategy to simultaneously weaken the masters and prevent any counterattack through an innovative combination of elemental magic augmented by invisibility, homing and resistance weakening spells facilitated indefinitely through Infinity. This approach was fearsome enough to defeat both high ranking demons in their true forms.
- Main article: Infinity
無限Infiniti」: An ability that allows Merlin to stop the time of her spells, causing them to last for eternity. The ability is so powerful that many label it as 'cheating'.
- Absolute Cancel「
絶対強制解除Abusoryūto Kyanseru」: By placing her hands over a spell, Merlin is able to completely erase it from existence. However, if the particular sort of magic is being sufficiently powerful, it may be difficult to erase completely, instead being temporarily suspended.
- Magic Cancel「
魔力解除Majikku Kyanseru」: A technique that allows Merlin to cancel any magic that has been cast on an individual. It was shown to cancel the effects of one of her own magical items.
- Magic Cancel「
探知Rokēshon」: A power that allows Merlin to locate any item or person. She can extend its reach to cover an area of approximately the size of a city.
- Power Amplify「
魔力増幅Pawā Anpurifai」: A spell that allows Merlin to amplify the magic of her allies, making their techniques considerably more powerful.
- Perfect Cube「
完璧なる立方体Pāfekuto Kyūbu」: A spell that denies entry to anyone but the caster. Originating from the demon world, the spell surrounds a specified area and reflects all attacks, whether strong or weak, back at the opponent.
- Shunkan Ido「
瞬間移動Shunkan Idō; literally meaning "Teleportation"」: High-level teleportation magic that allows Merlin to appear and disappear at precise locations and teleport groups of people instantaneously. The spell effect radius of Merlin's teleportation is several miles wide. Her teleportation magic was shown to be much faster than that of the Liones Kingdom's greatest magician.
物体転移Apōto; literally meaning "Object Transition"」: A subsidiary teleportation technique that allows Merlin to summon various objects, such as clothes and weapons, to herself and her allies.
- Cho-renzoku Teleport「
超連続 瞬間移動Chō Renzoku Terepōto; literally meaning "Super Continous Teleportation"」: This technique allows Merlin to teleport continuosly.
- Aqua Dress「
水の衣Akua Doresu; literally meaning "Water Dress"」: A spell that creates clothes made of water. By refracting the light in the water, Merlin is able to hide the most "important" parts.
- Wave Dragon「
波竜Uēbu Doragon」: A spell that allows Merlin to call many dragons made of water.
- Fire Storm「ファイアストーム Faia Sutōmu」: A spell that allows Merlin to attack the opponent with a powerful blast of fire.
- Exterminate Ray「
殲滅の光Ekusutāmineito Rei; literally meaning "Light of Annihilation"」: A spell where Merlin fires a disintegration beam, incinerating everything in the line of fire.
- Endless Whirl「
終わりなき渦Endoresu Wāru」: A spell with which Merlin creates a vortex of wind with an incredible destructive power, sucking their objectives towards its center. 
- Shock Stinger「
衝撃の尾針Shokku Sutingā」: A spell with which Merlin throws a lightning bolt at the enemy causing a great impact on his body.
- Magic Seal「
魔力封じMajikku Shīru」: A technique that seals away the magic of the objective.
- Icicle Castle「
氷柱の城Aishikuru Kyassuru」: A spell with which Merlin traps her targets inside huge pillars of ice.This spell was powerful enough to restrain Cusack for a brief period.
- Double Impact「
二重衝破Daburu Inpakuto」: A two-stage attack, where upon performing a sequence of hand gestures, the user unleashes a wave of force upon their enemies that combines the magical attributes of the four elements and multiplies it, and then set off a second, more powerful blast with a snap of their fingers that contains a weakening spell that decreases the resistance of the opponent. This spell is able to push back both Chandler and Cusack simultaneously in their true forms.
- Fake Ball「
偽玉Feiku Bōru」: A technique that combines attack magic with illusion magic; it prevents the opponent to know the true nature of a magic attack by camouflaging it with an illusion which makes it look like a different attack. 
- Chrono Coffin「
時の棺Kurono Kofin; literally meaning "Coffin of Time"」: A forbidden art that stops time.
- Curse Discovery「
露顕Kāsu Disukabarī; literally meaning "Discovery"」: A spell that is cast on someone who is afflicted by a curse. The spell will cause the curse to manifest in a physical form outside of the victims body. 
- Random Ball「ランダムボール Randamu Bōru」: Merlin launches a barrage of spherical bullets at the opponent.
- Purgatory Venom「
煉獄の毒Pāgetorii Benomu」: Merlin releases a small orb from her finger, which possess deadly poisonous properties.
- Power Limit Break「
魔力限界突破Pawā Rimitto Bureiku; literally meaning "Magic Power Limit Break"」: This technique allows Merlin to break the power limits in herself and her companions, increasing their magic power enourmously. It causes a great pressure in the body, as Merlin says that they must sleep an whole week after recieving it.
- Power Full Convertion「
全魔力合体Pawā Furu Konbājon; literally meaning "All Magic Powers Combination"」: Merlin fuses the techniques of her allies in a single powerful attack.
- Curses: Merlin is exceptionally accomplished in the use of curses, being capable of casting highly unique yet powerful and durable spells. Merlin's Curses were notoriously known to be practically impossible to remove, even by fellow powerful magic users. As seen where her former apprentice Vivian herself was incapable of removing the curse placed on her by her former mentor.
- Perpetual Reincarnation「
永劫の 輪廻Eigō no Rinne; literally meaning "Perpetual Samsara"」: A durable curse that causes the victim to reincarnate when they die and forget everything they did in their past lives. If the victim is given enough information regarding their true identity, their original race's traits and fragments of their memories will slowly come back. Once all their memories are restored, the victim will unavoidably die in three days in some way. If used on a Goddess, it causes them to reincarnate as a human but retaining their original power. The only known victim is the Goddess Elizabeth and the only way to remove the curse is to obtain a level of power equivalent to the Supreme Deity or the Demon King, if not superior. Merlin was noted by the Lady of the Lake to have reactivated this curse on Elizabeth Liones even after was freed from it's effects by Meliodas.
- Curse Engage「
呪いの婚約Kāsu Engēji」: A spell with which Merlin creates a contract between two beings to control one of them. By placing a ring on the hand of the victim, this is subject to the spell that causes excruciating pain in their body every time they try to use magic against the other person or the other person saying the incantation "Remada". Each time the spell is used, the person affected will be covered by brands that are becoming larger and once these brands cover their entire body, the affected person will die. The victim of the spell is unable to ever remove the ring.
- Perpetual Reincarnation「
- Combined Technique: Triple Prison「合技
三層牢獄Toripuru Purizun; literally meaning "Three-layer Prison"」: King combines Chastiefol's Pollen Garden with Merlin's Perfect Cube and Elizabeth's Ark to imprison the opponent in a three degree containment field. 
- No. 9: The Needle of Humanification: A syringe capable of giving a human body to any non-human creature with which it is injected.
- No. 48: Cure Angel: A demonic caterpillar-like creature that is used for healing.
- No. 91: Heat Fork: A large wooden fork able to heat things up.
- No. 172: Minimum Tablets: Based on the spores released by the Chicken-Matango, the Minimum Tablet is capable of shrinking the size of the consumer. The effects of one single pill can endure up to seven hours.
- No. 300: Monster Block: Bite-sized pieces of various monster and beast's meat.
- No. 401: Absolute Defecation Candy: A powerful laxative.
- Balor's Power Eye: Named after the One-Eyed God, Balor, the Eye grants the ability of viewing other character's fighting prowess in the form of numerical values which are split into 3 categories: Power, Strength and Spirit.
- Goddess Amber: A stone that will seal lesser demonic beings within a specific radius. It is used by Veronica to seal Meliodas on Hendrickson's orders.
- Incantation Orbs: A series of magical orbs that activate a spell upon destruction.
Merlin highly respects her captain, but Meliodas has shown criticism for using someone like the king as a magical guinea pig for testing out new techniques, though she brushes it off. The two possibly have, or had, a close relationship as Merlin believes that she may be forgiven for what she has done to Meliodas ten years ago. Also, among the various characters, Merlin is the only person to whom Meliodas has been willing to talk about more sensitive topics, such as his knowledge of demons, implying a deeper and/or longer relationship with each other compared to the other Sins. It is later revealed that the reason for their closeness is that the two have known each other for over 3,000 years, since the beginning of the Holy War, and since then the two have been preparing for the potential consequences of that war to once again return, mainly the revival of the Demon Clan and the Ten Commandments. Over the years, she has supported and even helped Meliodas form the Seven Deadly Sins specifically in preparation for these events.
Merlin has a one-sided crush on Meliodas. Merlin met Meliodas when she was a child and he saved her from the wizards who persecuted her. From that moment she developed romantic feelings for him, because Meliodas showed her a concern that nobody had ever given her. She did everything to win Meliodas' heart, including recreating herself in the body of an adult woman. However, Meliodas fell in love with another woman. Even so, despite the anger and pain that this caused her, Merlin never hated either of the two.
As a result of this long relationship, Meliodas and Merlin know almost everything about one another, and seem to be both equally close and cautious towards one another due to how much they know about the other. The best example of this is the fact that Merlin was the one who knocked Meliodas unconscious, stole most of his power and sealed it away in Istar 10 years ago when the Seven Deadly Sins were framed, an action that Meliodas was both curious and annoyed with when he finally learned she was responsible. In addition to this Merlin has shown little to no remorse for doing this, stating that it was necessary at the time, which also annoyed Meliodas. Merlin also took it upon herself to buy back Meliodas' sacred treasure after he sold it, knowing that he would eventually need it again. Unlike the other Sins, Meliodas was the only one to notice and question Merlin's hastiness towards returning to Camelot as well as noticing her injury from her encounter with Zeldris, showing concern for her as well as curiosity as to why she wanted to go back to Camelot so badly. Merlin reluctantly admitted the reason was because she wanted to find King Arthur, and even admitted to Meliodas how important he is to her, showing that the two of them are closer friends than they appear to be.
This was proven even further when she showed concern for Meliodas when he activated his own curse and completely unleashed his full power in his assault mode, to which she responded by asking Escanor to handle stopping him before he completely loses his emotions and control of himself. After their battle she tries to her best to suppress Meliodas, and she seemed concerned by her inability to help suppress his growing darkness. After he expressed his goal to become the next demon king to break his and Elizabeth's curses, Merlin seemed to be vexed and unhappy with his plan, being fully aware that his plan would not end the way he wants it to, and that it's not what he or Elizabeth truly want. After this, Merlin; like the rest of the Sins, wanted nothing but to stop his plan, as she was the one to suggest a trip to purgatory to retrieve Meliodas' lost emotions.
Merlin's relationship with Ban seems somewhat checkered, but the two have shown to be capable of getting along. Merlin was shown to calm Ban down when he threatened to attack Gowther in anger over the Goat's Sin of Lust's lack of empathy regarding Hawk's apparent death. Merlin also stopped Ban from destroying the remains of the gray demon in order to study it, despite Ban's strong desire to destroy the remains, which greatly upset him. Despite their differences, the two have both shown a moderate interest in each other's abilities. Ban once challenged her to a fight since he`never saw her full power before, but fell to her wits when Merlin dared him to do a hundred thousand push-ups just to tire him out, and in turn Merlin showed amusement in taking advantage of Ban's greediness and immortality to both test and mess with him.
Gowther seems to have a history with Merlin, as she was the one who gave him his armor, which explains her instantly recognizing him, while the other Sins only recently discovered his true appearance. Merlin also seems to defend Gowther's clueless and emotionless nature, which implies that she is possibly aware of Gowther's past, as well as the reasons for his unusual behavior. After Gowther is revealed to be a doll, by Merlin, it appears she was the only one who knew, and even explained to the others about how he was created by a great wizard. Both of these examples heavily implies the two had some sort of relationship long before their mutual membership within the Seven Deadly Sins, and/or that she was involved with him joining the Sins in the first place.
Merlin and Diane are on good terms with each other as the only female members of the Seven Deadly Sins, as shown with Merlin and Diane playfully debating what Great Holy Knight Zaratras would give their team, either a reward or scolding for their last mission, before discovering the murder ten years ago ; and later giving Diane her Minimum Tablets to allow the giantess to shrink down to human size and wear human clothes while her clothes are in repair. Merlin has since continued to use her magic to allow Diane to shrink down when needed.
The two have shown very little interaction between one another, and it is currently unknown as to how close they are in comparison to the rest of the sins.
While Escanor has a crush on her and wanted to look good in front of her, it is yet unknown if Merlin shared the same feelings towards Escanor, but she did insist on hearing the poem he had written for her and is interested in finding out the true nature on Escanor power. Merlin has also shown interest in which Escanor is the real one when his sunshine power changes his personality and confidence. This interest and knowledge of Escanor's power has given Merlin a great deal of confidence in him, so much so that she left him in charge of stopping Meliodas when he activated his Assault Mode, stating that he was the only one capable of stopping him while he was in that state. Even after their battle, she showed both concern for Escanor's injuries, as well as annoyance at Escanor for trying to shrug off his injuries in front of her as if they were nothing. When Escanor was about to die after the battle with the Demon King, Merlin admits that she only was interested in Escanor for the fascination with his power and she only see Escanor as another test subject. However, Merlin says that things could have been different if they had met 3,000 years ago.
Merlin and Elizabeth have a fairly good relationship, due to Merlin saving Elizabeth's father's life and the princess shows respect towards the mage like towards any other member of the Deadly Sins. After Meliodas revealed his past and the secret of his and Elizabeth's curse, as well as Elizabeth regaining the memories of her previous incarnations, Merlin's relationship with Elizabeth has visibly become only stronger. Merlin now shows the same level of care and concern for her as she had for Elizabeth's original goddess incarnation. During the aftermath of the fight with Melascula, the two exchanged warm pleasantries with one another, and Merlin even referred to her as "Big Sis Sis", as she used to do with the original Elizabeth.
Merlin and Hawk have a very good relationship as Merlin sees Hawk as a hero due to his action for saving Meliodas and believed that they should stick together due to them being both 'boars.' She also tends to refer to him as Sir Hawk and gave Hawk the Eye of Balor, as well as teasingly lying about his Power Level, so he would not be upset.
The two share a student-and-master relationship, and seem to be very close. It is not known how the two met, but Merlin seems to be somewhat protective of him, covering his eyes with her hand as Meliodas gropes Elizabeth and insisting on going to Camelot right away when she notices something happening there. They seem to have a mother-and-son relationship, as she took him in after his adoptive father died and was shown showing him how to read. She was very heart-broken when Arthur died, enough that she cried for the first time in 430 years.
Merlin and Elizabeth were acquaintances back 3000 years ago, when Merlin was 12-13 years old. According to Elizabeth, Merlin used to call her "Big Sis Sis". She also looked up to her as though she were her actual big sister Despite the fact that Elizabeth won the heart of Meliodas, whom Merlin was in love with, Merlin was never able to hate her.
Merlin learned the basics of magic from her father. However, given the nature of observation subjects in both, the relationship with him was very distant. There's not a speck of father-daughter love between them. In her childhood Merlin wanted her father to love her, but he only worried about developing her capacity for magic.
- Meliodas, Merlin, Arthur and the Holy Knights of Camelot vs. Albion: Win
- Meliodas, Diane, Merlin, Slader & the Holy Knights of Camelot vs. Galand: Lose
Defensive Battle for Liones arc
- Merlin vs. Grayroad: Win
New Holy War arc
- Assault Force vs. Zeldris, Chandler & Cusack: Indecisive
- Seven Deadly Sins & Four Archangels vs. Zeldris & Original Demon: Inconclusive
Demon King arc
Prisoners of the Sky
- Merlin & Escanor vs. Derocchio: Win
- According to the official fanbook/s:
- She is right-handed
- Before being framed, she held the Diamond rank
- Daily routine: Research and experiments
- Weak Point: Once she concentrates on something she forgets everything else around her
- Birthplace: Belialuin
- What she likes about herself: Being a passionate researcher
- Dream/Hope: Knowing everything
- Regrets: Being born
- The most embarrassing thing in her life: The one time when she confessed her love
- What she wants the most right now: Lifting the curse of the commandment
- Favorite animal: Mother of Chaos
- Favorite scent: Her research facility
- Favorite food: Raisins
- Charming point: Her suspicious smile
- She has no complex
- There is no person she respects
- She does not want to make an enemy of Meliodas
- In Arthurian legends, Merlin is the name of a legendary wizard and adviser to Arthur, the King of Camelot, as well the mentor of Vivian, who despised Merlin.
- Sometime after the Sins were framed, Merlin's old castle in the Kingdom of Liones started being used by Hendrickson as his Magical Research Facility, and overflowed with rare magical artifacts prior to its destruction. After Hendrickson's defeat Merlin started using another building to house various magic materials, though it is considerably smaller, appearing to be only a one, possibly two, story building, with what what appears to only be one room per floor, at least for the first floor.
- For yet unknown reasons, she did not use Location to find Escanor in an instant, despite being able to.
- Merlin's tattoo oddly resembles Hawk.
- Merlin uses magic to manipulate her clothes so that they stay on.
- In Volume 5 it is revealed during a Conversation between Hawk and Meliodas that the Tattoos of each Sin were created by Merlin using a Magic Spell.
- The Sin of Gluttony is usually symbolized with a Pig and the color orange.
- This makes Merlin the only one of the Seven Deadly Sins whose animal tattoo corresponds with the animal of the real sin that she represents.
- In the Nanatsu no Taizai Popularity Poll, Merlin was placed 9th (postcards only) in the first one and 11th in the second.
- Merlin has the biggest sweet tooth among the seven sins, being dependent on sweets when she is deep in thought.
- In the databook it was stated that Merlin once had several other apprentices before Vivian.
- In the extra page of Extra Chapter 10 that was only published in Volume 24, it is hinted that the person Merlin confessed her love to was Meliodas.
- Merlin seems to have a great tolerance to alcohol, since she says she would have to drink all the liquor from a tavern to get drunk.
- It is revealed that Merlin's body stopped aging at age 30.
- It has been revealed when she was 12 or 13 years old she looked up to Elizabeth (the original goddess) as her "big sis sis"
- Merlin revealed that the last time she cried was 430 years ago, after eating Meliodas' special Demon Frog Liver cakes.