Jack Skellington is the "Pumpkin King" introduced in Kingdom Hearts, and originally taken from the Touchstone/Disney film The Nightmare Before Christmas. He leads Halloween Town's yearly festivities, and is constantly searching for new ideas to make the holiday exciting. Unfortunately, his eagerness sometimes results in fiasco.
Kingdom Hearts χ
Jack's power is channeled by the Book of Prophecies to create the Jack Skellington, Jack & Sally, Jack Santa Ver, and Jack Skellington LM Ver medals.
When Sora, Donald, and Goofy arrive in Halloween Town, they discover that Jack has decided to use the town's newest arrivals, the Heartless, to take terror to a new level for the year's festival. In an attempt to make the Heartless dance with him, Jack enlists the services of Dr. Finkelstein to create a guidance system to coordinate their movements. Unsatisfied with the results, Jack decides they need a "heart".
Sora offers his help in constructing the heart, unlocking the heart-like container for Doctor Finkelstein, and Jack accompanies Sora and company in gathering extra ingredients. When the Heartless become hostile following the doctor's first attempt at using the heart, Jack fights alongside the others.
Sora, Jack, and the others obtain the remaining ingredients for the heart, including "memory" from Sally, who asks Jack in vain to reconsider using the Heartless. They return to the doctor's lab with the ingredients, but the finished heart is stolen by Lock, Shock, and Barrel, and Sora, Jack, and company give chase. They follow them to Oogie's Manor, and although they fail to recover the heart before the pranksters send it to Oogie Boogie, they give the three of them a sound beating.
Upon confronting Oogie in his torture chamber, Jack demands the heart back, but Oogie swallows it and attempts to use its power to control the Heartless. The group defeat Oogie, but as they are heading back to town, Oogie fuses together with his manor, forcing them into battle again. After Oogie is defeated once more, Jack watches Sora lock the Keyhole of Halloween Town.
Back in town, Jack laments not listening to Sally, who tells him that they'll come up with a new plan for Halloween together. Jack gives Sora the Pumpkinhead keychain and invites him to visit anytime.
Kingdom Hearts Chain of Memories
A memory-based projection of Jack appears in the memory Halloween Town within one of the rooms of Castle Oblivion. When Sora and company enter, he makes a frightening entrance, scaring Donald. He takes the group to see Dr. Finkelstein in hopes of finding a way to get rid of the town's Heartless. The doctor sends Jack to retrieve his memory potion from Sally, and Sora comes along.
When they find Sally, she expresses concern of what would happen if someone drank the potion, while Jack is excited. When Oogie Boogie steals the potion and takes off, the group goes after him. They catch up, but Oogie drinks the potion, and they fight and defeat him. Back at the lab, after Sora turns down the chance to drink the leftover drops of potion, Jack tells him that fear and doubt are the signs of a strong heart, and he sends them on their way.
Sora can summon Jack during battle as a friend card.
Kingdom Hearts 358/2 Days
While Roxas is engaged in a mission in Halloween Town on Day 149, Jack is planning the next Halloween festivities. He is at a loss for new ideas, but he gets some inspiration when he catches a glimpse of Roxas leaving the world through a Corridor of Darkness.
During his next mission to Halloween Town, Roxas sees Jack presenting an idea to Doctor Finkelstein, decorated balloons that contain terrifying surprises. The doctor approves of the idea, although Jack is still not satisfied. Roxas later sees Jack and Zero in the Graveyard, where the ghost-dog shows Jack that some balloons contain Heartless. Jack figures that someone else has decided to place the Heartless in balloons to add an extra level of terror. Jack continues brainstorming, hoping to prevent this other individual from coming up with better ideas before him, and when he gets a new idea, he gives Zero a bone and heads for Dr. Finkelstein's lab.
When Roxas returns on a later mission, Jack has had the Doctor build giant lanterns for him to use for grand entrance. Although he still isn't satisfied, he is further inspired by the explosion when Lock, Shock, and Barrel blow a hole in the wall of the Graveyard.
Roxas returns for Mission 62 to see that Jack has had Dr. Finkelstein create a freezing pumpkin-bomb. The Doctor approves of Jack taking inspiration from the world around him. The two briefly discuss the activities of Lock, Shock, and Barrel, but neither of them know what they are up to.
Jack witnesses from a distance the battle between Roxas and the Leechgrave during Mission 66, and seeing Roxas's black coat and the Tentaclaws give him an idea. By the time Roxas returns to the town square, Jack has erected a scarecrow combining the two images, with plans to make more. Although Dr. Finkelstein is impressed, Roxas is less so.
Kingdom Hearts II
One day while walking through the Hinterlands with Zero, Jack discovers a clearing with trees decorated with festive doors. He opens a door shaped like a Christmas tree and falls through into Christmas Town.
When Sora, Donald and Goofy arrive in the Town Square, which is decorated with Christmas lights, Jack arrives in a makeshift sleigh pulled by skeletal reindeer. He wishes them a Merry Christmas and tells them that he is running Christmas "again". They visit Sally in Dr. Finkelstein's lab before Jack heads off to bring Santa Claus, but he comes back to tell Sora that Heartless have appeared in town. Jack helps the group defeat the Heartless and asks them to be Santa's bodyguards. They all travel to Santa's House in Christmas Town, but Santa is less than pleased to see Jack after the last time he tried to run Christmas.
When Lock, Shock, and Barrel invade Santa's factory with Maleficent's help, Santa sends the group after them, and they follow the pranksters to Curly Hill where they defeat the Prison Keeper. When Lock, Shock, and Barrel run off to see Oogie Boogie, Jack and the others are surprised to learn that he has been revived. On their way back, Sally tells them that Oogie has kidnapped Santa Claus and is headed for Christmas Town. They return to the Toy Factory, where they defeat Oogie Boogie.
Afterwards, Sally gives an excited Jack the Santa costume she had been working on, but Santa convinces him that they should each stick to doing the jobs they love and do best, and Jack, newly inspired, heads towards Halloween Town with the Mayor, who has come looking for him. As he leaves, his costume reveals the next Gate.
When Sora, Donald, and Goofy return to Halloween Town, they find Jack, still in costume, picking presents off the ground in the Hinterlands. Although Sora is skeptical, Jack explains he just found the presents and is only returning them to Santa. When they arrive at Santa's House, Santa informs them that a large number of presents have been stolen from his factory, and Jack volunteers the group for finding the thief. Although they find Lock, Shock, and Barrel in the Wrapping Room, they claim they are only looking for parts for Dr. Finkelstein's experiment and have no interest in Christmas presents.
Sally arrives with news of Heartless with presents in Halloween Town, so the group return and recover the gifts, only to discover the Doctor's experiment has also been stolen. Jack decides to set a trap for the thief using decoy Christmas presents, and they discover the thief to be the experiment itself. In gratitude, Santa lets Jack ride with him in his sleigh. After Jack returns, Sally helps him realize that meaning of giving a present is not the gift box, nor the present inside it, but the wish to make someone happy, and the two dance in the snow.
Some time after Xemnas's defeat, Jack is seen, sans costume, discussing plans for the next Halloween with everyone in the Doctor's lab.
Jack is an extremely thin and equally tall being, his legs being over twice as long as his torso. He is a skeleton, and so his head lacks hair and sports empty eye sockets and nostrils. Strangely, his neck is solid, not showing vertebrae segmentation. His skull is similar, showing no distinction between his upper and lower jaws. His mouth is thin and wide, marked by a number of small "seams", similar to a Glasgow smile. Jack is missing several teeth in a number of different places. Unlike his head and neck, Jack's hands do show joints.
Jack's usual attire is a macabre black suit with white pinstripes. The top has a single white button, and a white shirt is visible underneath. His black dress shoes are bizarrely small in comparison to the rest of his body. The coat tails of Jack's coat reach to about knee-length, and he wears a large, black bow-tie shaped like a bat with several white veins in its wings and white eyes.
When masquerading as Santa Claus, Jack dons an obviously fake white beard (the part of the beard that should attach to his chin dangles a few inches from it) that reaches to the top of his thighs. His faded red pants have a vertical seam on the front, and his black, knee-high boots have fur lining at the top. Jack's tails in this outfit are about the same length as his normal ones, and he wears a maroon belt around his waist. His long sleeves are also fur lined at the cuffs. Finally, his faded red Santa hat also has white fur lining around the rim and a white fur ball at the tip.
Because of Jack's extreme height, he doesn't need to run to keep up with Sora. Instead, he is seen speed-walking throughout the series.
Jack is shown to be incredibly eccentric, always alive and active. He is somewhat of an optimist; when he puts his mind to something, he will not stop until he achieves it. He tends to be slightly oblivious, and never thinks things through, which usually leads to disaster. Though capable of learning from his mistakes, Jack does attempt a second try at bad ideas, such as using an the artificial heart and trying to understand Christmas. However, he is a generally cheerful character who is greatly respected by all, with the exception of Oogie.
Jack is innovative when it comes to planning Halloween celebrations, having stated he "[takes] inspiration from the world around [him]"; Dr. Finkelstein notes it was a quality usually found in scientists. Jack enjoys creating new inventions, such as a Blizzard exploding pumpkin, the scarecrow he based on Roxas, and the Leechgrave.
Jack does not equip a weapon, but his attack power and MP are still relatively high. Jack has two equipment slots and three item slots. Instead of physical attacks, Jack casts magic which is similar to Sora and Donald's, but incorporates Halloween themes.
Jack's combat abilities consist entirely of offensive special attacks. Applause! is his only physical skill, causing him to slide into enemies. The rest of his repertoire includes magical spells of four different elements: Blazing Fury launches a fireball, Icy Terror fires ice crystals, Bolts of Sorrow summons thunderbolts, and Ghostly Scream conjures dark energy. Jack's Support abilities include Treasure Magnet, Jackpot, Cheer, and MP Rage.
Kingdom Hearts Chain of Memories
Jack appears as a friend card in Halloween Town.
When a Jack card is used, Jack appears on the field and casts magic spells, which can be either Fire, Blizzard, Thunder, or Gravity. Stocking two or three Jack cards creates Surprise! Lv2 or Surprise! Lv3 respectively, increasing the amount of spells Jack casts and the tier of magic he uses.
Aside from his friend sleights, the Jack card can also be used in two magic sleights. Firstly, combining a Jack card with summon cards creates Terror, a sleight that scares away enemies. Secondly, stocking Jack with magic and summon cards creates the Gifted Miracle sleight, which reloads cards and restores HP to both Sora and his enemies.
Kingdom Hearts II
Jack is a magic character with spells similar to Donald and Sora's, but with a decisively Halloween theme. As such, his ability list is very similar to Donald's and he tends to burn through his MP quickly. Jack has no armor slots, two accessory slots and three item slots. His "weapons" are his own fists.
Jack's action abilities are Blazing Fury, Icy Terror, and Bolts of Sorrow, which correspond to the elemental magic spells, Fire, Blizzard, and Thunder respectively. His limit, Applause, Applause, involves Jack and Sora dancing as impulses of spooky magic are released.
Jack originates from Tim Burton's 1993 stop-motion Disney film, The Nightmare Before Christmas, voiced by Chris Sarandon with composer Danny Elfman as his singing voice. Wanting something new to keep Halloween from being so tiring year after year, Jack goes for a walk in the woods and uncovers Christmas Town. Amazed by its magic, he decides to take over Christmas with disastrous results, but he eventually saves the day.