This is Diane a member of the Seven Deadly Sins and is known as the Serpent's Sin of Envy. She is a member of the Giant Clan, and is thus much larger than ordinary people, including her fellow Deadly Sins. Her Sacred Treasure is the War Hammer Gideon, which she uses in conjunction with her inherent power, Creation.
As a giant, Diane is several times larger than an ordinary human being. She is a fair maiden, with purple 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 Seven Deadly Sins, her facial appearance is relatively childlike and has shown little change over the years. Diane's wanted poster depicts her with light colored hair. Her symbol, which is of the Serpent, is located on her left outer thigh.
When she was still a child, Diane wore ragged clothing until King made her a new set. Her clothes during the earlier part of the series resembles what King made for her, having sewn it herself by using leather deirived from Dusk Bison skin.[2] Her earlier attire consisted 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 blue-grey leathery material covered in shiny steel stud - with the right gauntlet having been destroyed by Gilthunder during the fight in the Forest of White Dreams. She also wore a backpack previously used by Meliodas.
Ten years ago, Diane—as a Holy Knight—wore a full body orange armor with a unique helmet like the rest of her fellow Deadly Sins.
Diane's current clothes is made by Merlin and is almost the same style as her previous one, except for an inverted triangle cut on the chest, and the skirt. She is also wearing black underwear underneath the skirt.
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 [3] and becoming very delighted from compliments.[4] Her feelings are strong enough for her to overcome her fears for his sake.[5] However, she is very quick to throw temper tantrums, and often does so upon becoming upset.[6] Diane also gets angry and jealous when Meliodas does perverted things to other girls.
Due to her size, she cannot help Meliodas in any way other than fight for him. She has expressed her strong desire to be smaller, contrary to Elizabeth's desire to be strong.[7] Despite Diane stating that she has no interest in humans, she still selflessly saves people who are in danger, like when the elderly man in Vaizel and Zeal were at risk, Diane risked her life to protect them.
Despite her brave and strong appearance, Diane is a somewhat emotionally fragile person, as shown by her hatred of loneliness. This was portrayed when she was a child and insisted that King stay by her side when she was sick instead of getting herbs to heal her, and when she waited in tears for him to return to her. Diane showed the same kind of feelings towards Elizabeth after she was kidnapped by Vivian.
Many years ago, Diane left the Giant's Clan due to her hatred for fighting. After her departure, she formed two rock-like golems to accompany her, despite either of them being unable to talk. She was always alone playing with them as there were no other living beings who would accept her.
At one time however; Diane found an injured King lying unconscious on a riverbank and nursed the fairy back to health. King, who had taken a hard blow to his head, had lost all memories of his past and in his gratitude spent the next five hundred years playing with and protecting Diane. Diane later met an old man, a human, who offered Diane and King some food despite them 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 stopped him, telling him to not ever leave her side since she didn't want to be alone anymore. The old man who gave them food found them, and concocted a 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 ended 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 man they believed was the hunter they had met was actually the late hunter's grandson. 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 was on fire. King told Diane to stay back as he went to the town, promising to come back. Diane waited in tears, hoping for King to return, only to find King return and strike her with a flower to her spine to erase her memories of him. Diane eventually awoke from her slumber without any memories, but curiously picked up King's flower and walked outside. She rejoins the Giant's Clan afterwards.
Several hundred years later, Diane had grown into a woman, and was in midst of being trained by Matrona to become the strongest Giant warrior alongside another fellow giantess, Dolores. One evening, Diane overheard Matrona's plans to make Diane the strongest Giant warrior ever. Disliking Matrona's plans for her, Diane made up her mind to leave the village once more. She goes to find Dolores and run away with her, but Dolores declines. Dolores explains after much thought, the Giant's village is the only place where they'll ever be accepted, and that there was nothing to fear once you've been accepted.
