Diane

Diane is 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, described as "lovely, beautiful" with purple eyes and medium length brown hair which is tied up into large twin tails. She has a well-developed and curvaceous body. Similar to 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 derived from Dusk Bison skin. 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  and becoming very delighted from 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. 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, 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. As a member of the Seven Deadly Sins, Diane is shown to be incredibly strong. She was able to punch the ground and use it 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 an extraordinary connection with nature, being able to create two Golems. Matrona, who trained her all her life, said that Diane had the potential to become the strongest warrior of the entire Giant Clan.

After passing the trial, her connection to the earth increased to where she can increase her power farther while dancing. According to Melascula, her strength became comparable to Drole's. Drole himself believed that eventually she will become a greater ruler of the Giant Clan than himself because her love made her stronger than mere combat power. Immense Strength: Since she's a giant, Diane is able to perform staggering feats of strength, able to clash with the likes of Meliodas in terms of strength and even break through barriers capable of withstanding meteors with a single punch. She can swing a war hammer with a weight of 998 kg (2200 Pounds). Enhanced Speed: Using her strength, Diane is actually incredibly fast and agile, however due to her giant size this speed is reduced to nil, but when shrunken to human size her speed increases and is able to dodge rapid arrows shot by a foe of similar ability such as Gowther. Immense Endurance: Due to being a giant, Diane is able to withstand several mortal blows, such as being pierced through the shoulder and thigh and still move fast enough to save citizens from collapsing buildings, and still retain consciousness even after losing blood and taking a further beating. Enhanced Durability: Being a giant, few attacks are powerful enough to actually cause grievous harm to Diane and she can shrug all but the most powerful attacks off powerful Holy Knights. 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. 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.