TV-Series
Description
John Doe, known as "The Chaser," is a dream demon from the Dream World who commands an army of feline minions called Little Chasers. His goal involves crossing into the human world by possessing a suitable vessel—Yumeji Fujiwara—whose recurring nightmares made him a target. For an extended period, John Doe orchestrated nightly pursuits within Yumeji's dreams using his cat minions to erode the boy's mental defenses for possession.

He appears as a tall figure (191 cm) clad in a black suit, white gloves, boots, and a red hooded cape. His face hides behind a white skull-like mask that conveys expressions despite its static form. In the human world, he manifests as a black cat with a cape-like accessory. He wields a saw-guillotine sword for dream-realm combat, and his personal dimension—a small cityscape called his daydream—anchors his existence and power.

John Doe first lured Yumeji into this daydream to explain his possession plan, but Merry Nightmare intervened and defeated him. Retreating after the confrontation, he noted he gained valuable insights. Later, when Engi Threepiece gravely injured Yumeji, John Doe reappeared. Though acknowledging the opportunity to claim Yumeji, he instead healed him and revealed dream demons were drawn to the human world by Hercules' light. This act signaled his shift from antagonist to ally, declaring himself an "ally of truth."

His abilities include exceptional speed, allowing instantaneous repositioning in battle. He commands Little Chasers, extensions of his daydream that can materialize within 10 kilometers of him in the human world. His strength fluctuates with his daydream's scope.

His dynamic with Yumeji evolved beyond hostility: he mentored the boy in creating the "Lucid Gadget" power-replication technique and aided him against threats like Noir and Landsborough. Though aloof, his Little Chasers exposed his genuine intent to help. To stay in the human world permanently, he claimed a cat as a vessel and resides with Yumeji at the Tachibana household, accepting the name "John" while rejecting alternatives. During the Hercules conflict, he supported Yumeji's strategies and became the first dream demon to undergo "Vessel Transfer," enabling their combined "Ultra Lucid Gadget" transformation.

John Doe arrived in the human world roughly a year pre-series, lured alongside other demons by his Little Chasers' reports of the Gatekeeper's disappearance and Hercules' abduction of a girl. His actions stem from a desire to uncover the truth behind these events, declaring himself a "chaser of truth" dedicated to revealing hidden realities over conquest.