How Diane joined the Tourney
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.
Diane left the village once more alone, and soon 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. Diane's encounter with Meliodas has her run straight home to tell Dolores that there was another place they could be accepted. When Diane arrived at the village, Dolores was revealed to have been killed by mountain bandits on a bodyguard job. After Diane learned that Matrona was the one who sent Dolores, she punched her in anger, upset knowing her friend would rather die, than wanting to fight.
The day after, Diane and Matrona were hired by the Knights of Liones as mercenaries to help in taking down foreign savages. This was all a ruse however, as the knights' true objective was Matrona, looking to gain reputation and prestige for taking her down. Diane and Matrona engage in battle against the traiterous Holy Knights. In the midst of the brawl, a poisonous arrow was about to hit Diane, but Matrona took the arrow in her place, severely crippling the Giant warrior chief. Despite being weakened by the arrow, Matrona used the last of her strength to take down Gannon and 330 other Holy Knights before supposedly dying. Diane mourned for Matrona's death before being captured by the Knights of Liones and arrested under false crimes. She was sentenced to capital punishment under the pretense of killing Matrona in jealousy, along with the deaths of 330 other Holy Knights to an attempt to silence all witnesses. As her punishment was read aloud, Diane was saved at the last moment by Meliodas who gained legal custody over her.
While on a mission to wipe out a group of vampires who had taken over Edinburgh castle, Diane, who was partnered with King, were suddenly weakened due to a drunken Ban's deliberate use of Snatch and as a result, the two had a hard time in battle against two Vampires, Mod and Ganne until they were saved by Gowther who had made the two vampires believe he was a part of their family and started to kill and attack one another. Diane and King were soon upset over Gowther for not coming sooner, who revealed he wanted to make it exciting.
The Seven Deadly Sins, including Diane, were summoned to a castle to meet the Great Holy Knight Zaratras 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.
After the fight against Gilthunder, Diane finds an otter family under hostage from the Holy Knights. One of them is Mrs. Otterton.
Character Select Screen Animation
Diane cracks her knuckles.
After the announcer calls her name
Reaches the ground and scoops a rock as the camera zooms saying "some Holy Knights got in, huh?"
Ground Gladius (Neutral)
Diane's sacred treasure weapon, Gideon is slammed into the ground, raising the earth up into a sharp, gigantic spire with the appearance of a blade, cutting the opponent.
Double Hammer (Side)
As she is spinning Gideon behind her back, Diane summons two stone fists from the ground on both sides of her opponent. She then performs a hand sign to crush the target between them.
Rising Meteor (Up)
Diane jumps and raises Gideon high above her head, erecting an enormous star-shaped pillar from below her opponent. The pillar hits the target at an incredible speed, the force of which traps them against the pillar as it extends toward the sky.
Mother Catastrophe (Down)
The earth is torn apart with a single strike of Gideon. The debris, from the strike, is launched high into the air and gathered to form a massive mountain like structure that falls towards the ground and crushes anything caught in it's wake.
Rush Rock (Hyper Smash)
Diane uses her power to raise a number of jagged rocks from the ground. These rocks are then rapidly fired at her opponent.
Fillet and Loin (Final Smash)
After performing multiple hand signs, Diane summons a pair of golems, Fillet and Loin, to pummel her enemy.
- Diane slams Gideon into the ground, causing pillars to rise, then says "So it's just the two of you then?"
- Diane stomps the ground, then punches a rock and says "Guess I'm always the one who jumps to conclusions, aren't I?"
- Diane does five punches then drops her heel and swings Gideon then says "You'll have the help of the Serpent's Sin of Envy, Diane!"
Diane walks in and creaks her head saying "You're in trouble, Holy Knight."
- Diane's rival is Emmitt Otterton's wife, Mrs. Otterton.
- Diane shares her English voice actress with Monet, Ampilus, Dragonair, Sailor Uranus, Gon Freecss and Naotora Ii.
- Diane shares her Japanese voice actress with Mitsuami Jubei Yagyu, Platinum the Trinity and Iris.
- Diane shares her French voice actress with Xingcai and the Blue Pinchley of the Scurvy Crew.
- Diane shares her German voice actress with Charlotte Christine de Colde.
- Diane shares her Arabic voice actress with Zhang Chunhua, Opal, DoorMouse, Ruby Biggle, Wheelie Scooter, Sylia Stingray, Natsuki Kuga Ni, Reiko Nagase, Nanocarp, Lunatone, Lanturn, Ms. Masamune Date, Rukia Kuchiki, Nami, Shanoa and Elphelt Valentine.