Isolde

is a Holy Knight of Liones, serving under the Tristan Platoon of prince Tristan Liones.

Personality
Isolde takes her duty seriously and willingly protects the kingdom and the royal family, specifically Tristan.

However, she can be emotional shown when she was questioned by Tristan why she chased Percival and broke down crying. Isolde has an almost low opinion of her attractiveness as a woman, because of her extensive height something that caused her to be teased by others. It is shown that she's deeply in love with Tristan, who is the sole person who didn't mock or tease her, even gifting Isolde her ribbon. She can also be rather critical of herself, when it comes to her feelings for him.

Chaos in Liones arc
Isolde first appears within the Kingdom of Liones, where Percival crashed into her and ended up under her skirt. Enraged by the boy's insolence, Isolde chases and attacks him before uniting with her fellow Tristan Platoon members Chion and Jade, whom then team up with her to eliminate the boy despite his attempt to reason. While the air around Percival is being blocked by Chion, Isolde continues her assault, but Percival activated his power which absorbed her explosion and blows her away.

Returning up on her feet when Percival's friend arrives, and while Percival's head is enclosed with darkness, Isolde attacks his friends. The assault stops with the arrival of prince Tristan.

After clearing up the misunderstanding, Tristan asks Isolde why she attacked Percival in the first place. Isolde just walks away crying saying that she is too embarrassed to look Tristan in the face again.

Isolde is left by herself on a ledge crying where is founded by Gawain. Gawain attempts to comfort her despite her reluctance due to her infatuation with Tristan. However, Isolde notices a fight going on in the east where Pellegarde is fighting against Pelliot and other Holy Knights of Liones. Some resulting debris from the battle, flies right at Isolde, forcing Gawain to use her power to shield her as she declares herself "Master of the Sun".

Isolde joins the fight against Melagaland along many other Holy Knights. She supports Dreyfus using her Time Bomb to leave time delayed explosives on the demon. Isolde later manages to free Percival before Melagaland kills him, to which Melagaland attacks her, subtracting meaning from the source of her power, however Tristan manages to save Isolde from being crushed by Melagaland. Tristan then leaves a wounded Isolde with Hendrickson before going back to fight.

Wallnack arc
The morning after the battle, Isolde meets Anghalhad after training and the two girls manage to come to terms. Isolde tells her how she was always discriminated for her looks and size by everyone except Tristan, that's why she wants to keep fighting for him even if she no longer has the right to love him after Percival took her chasity away from her. Anghalhad clears up the misunderstanding and leaves Isolde embarrassed about what it really means to lose her chastity.

Isolde and the rest of the Tristan Platoon participates in the meeting in the war room to discuss the situation with Camelot. She allows a little Gawain to sit on her lap, asking if she really is one of the Four Knights of Apocalypse. When Thetis teleports everyone to a landscape that has been stripped of various parts, leaving only empty spaces, Meliodas explain that it is the result of Arthur creating a new Camelot, something he heard from Percival's grandfather who was a former Holy Knight of Camelot. When everyone is left despairing that they have no way to get to Camelot, Isolde and the others are shocked when Percival suggests they go on an adventure together to find a solution.

As they walk through the kingdom, Isolde asks Tristan if he's better now, to which he tells her that he's still in pain even though his wounds are healed. Isolde reproaches him that he was so careless because of her and that the Tristan Platoon should protect him and not let him risk his life for them. Tristan thanks her for her intention but tells her that as partners, none is more important than the other, saying that he always wanted to be like the legendary Seven Deadly Sins next to them. Isolde kneels before him thinking that as long as she can give her life for Tristan, she doesn't care that he doesn't see her as more than her friend or companion. Tristan then gives her a new ribbon to replace the one that was destroyed which Isolde gladly receives. Gawain, who was being ignored in the whole situation, decides to leave saying that they can talk about love and lose chastity, leaving Isolde embarrassed.

On the day that everyone will finally set off in search of a way to Camelot, Meliodas divides the Four Knights into search teams. The Tristan Platoon is assigned to go to the old Camelot.

After leaving, the group arrives at Wallnack deciding to all stay there one night before splitting up in Dalmary. There Isolde is glad to see everyone preparing for the festival in honor of the dead, which she had already attended along with Jade and Chion. At the inn, Isolde ends up sharing a room with Anghalhad and Gawain. Isolde tells Anghalhad that she is worried that Tristan will end up sharing a room with a smaller, more attractive woman who might seduce him. Isolde and Chion end up going to see who Tristan is with, misinterpreting what they hear through Chion's Sylph when Tristan was just buttoning the shirt of the woman he was with, leading Isolde to break down the door in a huff. After dressing that woman herself, Isolde decides to stay in that room instead of Tristan, when the inn owner chides her for damaging the door. When Tristan is taken to the festival by that woman, Isolde and Chion follow them, getting nervous when they lose sight of them and ask the others to help them find them.

When everyone briefly manages to feel magical presences again when Gawain's Absolute Cancel undoes the spell over the town, Isolde runs to where she sensed Tristan, but Anghalhad goes after her, warning her that she also sensed another presence nearby. The two are surprised by Jade, causing Isolde to attack him with her morning star. Jade and Isolde have a loving conversation about their long time knowing each other, tacking Anghalhad attention. However, they are attacked by Teaninich's arrow.

Teaninich first delights in being able to kill two beautiful women, but is upset when she thinks Jade is watching her with perverted intent. Jade clarifies that she was looking at her weapon, which is useless since she has no more arrows, but Teaninich reveals that what she shot was not an arrow. The projectile, a snake controlled by Teaninich's Summon Creature power, comes out and bites Isolde on the leg, poisoning her. As more creatures come out to attack, Jade deals with blinding Teaninich with Darkness and carrying Isolde on her back to escape her. Isolde leaves her Lover's Mine to prevent Teaninich from following them. They end up lost in the alleys of the town. Jade sucks the poison from Isolde's wound though he regrets that he can't do more for her like Tristan would. Isolde says that he equal helped her, such as a time when as children they got lost in a forest and were attacked by monsters, with Jade carrying her safely back. Jade is grim to hear what didn't really happen, but when Isolde says that she always wanted to thank him, Jade asks her out on a date although Isolde takes it as a joke. Jade finally decides to confess his love to her, but then Macduff surprises them by removing all sound with his magic.

When Isolde manages to detonate one of her bombs on Macduff, Jade uses his Flash to surprise him while the light prevents him from seeing. However, Jade realizes that Macduff is blind. As Macduff is about to attack Isolde, Jade steps in, ending up with his chest pierced by his arm. Isolde despairs at Jade's eventual death, saying that she will go on a date with him if he wakes up. When the rest of the group arrive and fail to save Jade, Isolde is heartbroken. When everyone returns to the inn, Isolde says that it's her fault Jade died since she did it to protect her. Anghalhad tries to console her by saying that her fault lies with the enemy.

The next day, after giving care of Jade's body to Thetis, Tristan introduces Ioladio to the rest of the group stating that she can give them information to get to Camelot. Ioladio apologizes because her magic was responsible for one of them dying, to which Anghalhad says that they won't forgive her if her information about Camelot is not useful. Ioladio affirms that yes, but that to get it they must accompany her to the Demon Realm.

Demon Realm arc
Arriving at a strange archway, Chion accuses her of reaching a dead end. However, Ioladio asks Percival to put his head in the arch, revealing that the entrance is hidden by an illusion. Finding a long spiral descent, Tristan points that his horse can't go trough a so narrow road, but Donny solve this with his Telekinesis. Along the way, Tristan apologizes to Lancelot that he will no longer be able to reunite with his parents in Benwick as his carelessness caused Jade's death. Isolde jumps up, claiming that he didn't do anything wrong, because everyone is there with him because they chose to. The rest agree, although Percival doesn't fully understand the situation.

Coming to the end, Gawain remarks that they have two problems to deal with. The first is the corrosive miasma of the Demon Realm that kills all non-demons. Tristan uses his Saint Coat to cover everyone in a protective layer of light, Gawain questions if it lasts a day, but Tristan admits it only lasts six hours, to which Gawain tells him that he should train more. When Percival asks what the second problem is, Gawain reprimands him for using his brain, since it is public knowledge that there is widespread hatred of demons and other races, which would pit demons against trespassing humans. Confirming this, Ioladio says that she doesn't blame them if they don't want to move on. However, they all confirm that they want to continue.

After exiting through one of the holes of a large relic in the Demon Realm, they are all suddenly thrown into the void by a current of wind. As they fall, Tristan uses his wings to fly and catch Isolde. However, they are all surrounded by demons that demand to know their intentions.

Abilities

 * Isolde's magical power manifested from her love for prince Tristan. It allows her to release magic sparks from her attacks that act like explosives.

Weapons
Isolde uses a morning star as her weapon.

Chion
Isolde and Chion are friends since childhood.

Jade
Isolde and Jade are friends since childhood. Jade has hidden feelings for her since, but Isolde seems to be oblivious to that.

However, Isolde feels gratitude towards Jade for saving her from a Moss Dragon when they were children (though, unbeknownst to her, it was a lie said by Jade).

Tristan Liones
It is implied that she has feelings for him when she acted around Tristan when asked her why she chased Percival and she broke down saying she can't never see him the same again and ran away crying, thinking he will not like her anymore. Though she regains her confidence after talk with Gawain and a battle with Melagaland where she expressed her love to him.

Gawain
When they first met they seem to got along well. Though later on she did got a bit annoyed at times with Gawain hitting on her time to time but doesn't hate her despite that.

Trivia

 * Isolde is named after a character of from the legend of.