Jack-O-Lantern

Background
Jack is one of the core members of [Will-o-Wisp] and serves the eternal demon Willa the Ignis Fauutus.

Appearance
He has a pumpkin head along with a blue floating gown. He wears white gloves. Jack is mostly just a large pumpkin head wearing a purple gown with a red ribbon tied around the collar. He carries around a lantern held by his white gloved hands.

Personality
Jack has a gentleman like personality, always being polite and treating everyone equally and with respect. He often has a cheerful personality that really dotes on kids, but he has times when he is serious and filled with wisdom. When he learns that his opponent has hurt a child, he will go into a rage and his character will change drastically.

Relationships
Ayesha - he can be summoned by Ayesha, a spirit that controls natural gas. He often listens to orders from her as shown in Episode 8 when the two partners were dueling with Kasukabe You. He is normally seen with her the most when Willa isn't around, possibly due to her still being a young spirit that was saved and for being adopted by his master.

Will-o-the-Ignis-Fatuus - Creator of the Pumpkin Outfit and his master. It is difficult to say what kind of relationship they have but it is obvious they care deeply about one another as comrades and travel partners before they arrived at Little Garden.

Queen Halloween - The person who allowed both him and Willa into Little Garden. The community is on good terms with her as he asked for a favor on behalf of You and got permission to do so through the Queen's knight, Faceless.

Faceless - A knight for Queen Halloween.

Kasukabe You - Jack develops a friendship with the girl shortly after the game and was one of those trapped on the floating castle with her. They work well as a team and Jack was rather pleased with You's deduction skills.

Lauis Perseus - He is currently training under Jack.

Volume 2
Jack apeared with Ayesha during the Gift Game [Duel of the Creators], facing off against Kasukabe You. He is described as a Gift and destroying him is one possibility to win as the game declares you can either find the exit or destroy the opponent's gift. During the game Ayesha rode on Jack's back, until they both split up. Jack occupied You and revealed Ayesha's true nature and of the reason why Will o Wisps were caused; to find the bodies of dead people buried under the sites the small fires occur. In the end You surrendered and the victors were Jack and Ayesha.

Jack questioned You for her actions regarding why she attended the game alone. He gives her advice on that a community needs to trust one another and leaves after making a small joke of knowing nothing as he was a simple pumpkin.

Gifts and Abilities
He himself is a Gift with the power to create and possibly manipulate fire. During volume 4 he also shown the power to control little golems (or shikikami) of sorts in the form of walking candlesticks and floating lanterns.

Demonic Fire: Having been created by Willa the Ignis Fatuus, 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 You'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 You, Jack was easily able to outmanoeuvre the agile girl, surprisingly her several times. However when he wishes to move extremely fast he transforms into a large, blue fireball. He uses this form before the start of the Gift Game in episode 8 and in the Short Story Candle, Omelette Cake and Ghost Town.

Trivia

 * His favorite laugh is Yahohoho!