|Allies||Ayesha Ignis Fatūs|
|Anime Debut||Episode 8|
Jack, as is his namesake, is an enormous jack-o'-lantern given life. His head is a large pumpkin with a smiling face carved into it, and a fire inside lighting up his open mouth and eyes. The rest of his body is simple in design, being a disembodied purple robe that is tied around the neck with a red string, and two arms that end in large, white gloves. Jack is almost always seem carrying his lantern around, and as he doesn't possess legs, he instead flies for movement.
Despite his ominous appearance and nature, Jack is actually a very kind and supportive person. Always addressing people with a polite tone, he didn't hesitate to give Yō some advice on living with a community after seeing some loneliness in the young girl. This caring personality extends to anybody he meets, as he showed concern for the safety of several children during Grim Grimoire Hamelin's attack on the North Side, and offers advice to his partner Ayesha on several occasions.
The Piper's GameEdit
Joining Ayesha in her match against Yō in the tournament during the Celebration for the Rise of the Fire Dragon festival, Jack flies into the arena with his partner riding atop his back, who then introduces him as the best Gift of the Will-o-Wisp. Being transported into the game's stage by Shiroyasha, Jack and the others listen as Black Rabbit explains that the game will be Underwood Maze, with the goal being to escape the enormous tree or destroy the opponent's Gift.
Following Ayesha's command, Jack chases Yō throughout the maze, igniting the gas produced by his partner in an attempt to stop their No-Name opponent. After racing throughout the tree for a while, Ayesha grows impatient and leaves Jack to deal with Yō, the jack-o'-lantern being told to give it his all. No longer holding back, Jack quickly appears before Yō and strikes the girl with his empty hand, sending her crashing into some roots. Cutting off the girl's escape with some fireballs, Jack reintroduces himself as the Gift created by the great demon, Willa the Ignis Fatūs, and that his fire is the same as fire produced by a demon. Explaining that their community accepts wandering souls such as Ayesha to grow in power and fame, Jack traps Yō in a surrounding wall of fire, forcing the girl to surrender.
While Ayesha accepts her victory before the crowd, Jack goes to Yō and asks why the young girl had chosen to participate alone during the game despite being allowed a partner. Noting the loneliness in her eyes, Jack advices that by being in a community, she'll have to rely on other people sometimes. Apologising for prying into her affairs, Jack then leaves with Ayesha.
During Grim Grimoire Hamelin's attack on the city, Jack and Ayesha help evacuate the civilians and subdue several soldiers who fall victim to Ratten's hypnosis, protecting Lily and another girl in the process.
Powers & AbilitiesEdit
Demonic Fire: Having been created by Willa the Ignis Fatūs, Jack is capable of producing flames similar those of the great demon. He is able to produce these flames from either his lantern or his mouth, and manipulate it to the extent that he can create fireballs or a stable wall of fire to trap an opponent in. Though powerful, these flames can be dispelled by a strong enough force, such as Yō's wind-blasts. Jack is also able to ignite the gas produced by Ayesha, creating bright blue flames instead.
Enhanced Speed: Despite his large size, Jack possesses incredible speed, such that it almost appears like teleportation. During his battle against Yō, Jack was easily able to outmanoeuvre the agile girl, surprisingly her several times and eventually forcing the girl to surrender.
Appearance in Other MediaEdit
Hot Springs Tour ChroniclesEdit
Jack, once again following Ayesha, appears at the hot spring village in order to participate in the Ferry of Sukunabikona Gift Game. After greeting Yō and her friends, they are all then informed by Shiroyasha that they must complete several Little Games in order to progress. Jumping ahead, Jack and Ayesha lead the competitors towards the venues.
Jack accompanies Ayesha to an 'all-you-can-eat' Little Game, where Yō and Leticia are also participating. Due to being a Gift, Jack is forced to sit on the side. Warning Ayesha not to push her limits in the Game, the earth spirit ignores his caution and winds up knocking herself out by eating far too much, and Jack withdraws them from the competition.