Artificial Devil Kai is a mysterious creature in the form of a suit made by Kai from ingredients like the devil tumors and flesh of magic users. Only says “Gucha-Gucha.”
A mindless beast moved solely by instinct and few commands made during his creation, an amalgamation of four of the nine original head of Ai Coleman, this creature has no recollection of his life as Kai, or at least he's incapable to think like him, possibly meaning that his personality is a shared mind between individuals not related directly to the minds of Ai, Aikawa or Kai.
Having a primitive mind, only looking for food (a typical trait of Aikawa), and after Yasaka cut open his skull, the creature took a feral and brutal attitude cannibalizing everyone around him and showing Hole's presence inside him when he attacked Ton.
Created in a laboratory inside En's Mansion by Kai, using the flesh and Devil Tumors of Magic Users killed by the Cross-Eyes, the hide merged with Ai Coleman, after he regained the control of his body, showing his original rotten head replacing Aikawa's head, now dangling aside his body while crawling on the floor. During his creation, four bald heads with crossed eyes appeared instead of Ai, Aikawa, or Kai heads, fusing together with drain tubes appearing from their mouths, the hide made of sorcerers flesh combined with the four heads (now one big head with four faces) and the creature was born.
The monster has shown clumsiness trying to move for himself, not be even able to stand for his weight, the Tops officers of the Cross-Eyes helped him to get up and went through En's Magic Door to Hole, (The creature was able to create a magic door to reach Hole, but his massive body couldn't fit in the tiny door). The artificial devil constantly expulse Black Powder from the many tubes in his body, this attracted the attention of Yasaka, and some other recently enrolled Cross-Eyes, believing the creature was the source of black powder all along (not knowing he is the boss) they followed them to Hole.
In the human's realm, the creature was put beneath a bridge near the sewers where he started to eat trash, disgusted and worried, the Cross-Eyes went to the city looking for food, but they found nothing (thanks to the day prior of the Day of the Living Death, and all the stores in the city were closed except for the Central Department Store), leaving Dokuga and the creature alone. They were ambushed by Yasaka and his Cross-Eyes, leaving the officer for death, they kidnaped the creature and headed to the basement of the Central Department Store, where Yasaka murdered his partners to keep all the black powder for himself.
During the fight between him and Fujita, Yasaka was severely wounded in the head, having cerebral damage, he cut the creature's head trying to take his brains for himself, with this, the artificial devil went berserk and started to eat the corpses of the other cross-eyes in the room, even attacking Ton with a barrage of "Sludge" removing his Devil Tumor and devouring his body using the tubes on his head. When the other Top officers found what was going on, they felt sick and disturbed by the scene, Tetsujo, infuriated by this, tried to attack the monster, but it was repelled by Natsuki's defense type magic (wich Kai killed and removed her Devil Tumor, putting inside the hide with thousands of other tumors), with this, they found out what happened to her, and acknowledging the fact that they were merely disposable pawns for the Boss all along, Tetsujo once again unsuccessfully attacked the artificial devil. Enraged by the attacks, the creature used his tubes and killed Saji and Ushishimada, after that, he started to repeat "Sacrifice" over and over, opening a Hole to the Lake of Refuse beneath the Department Store, and throwing himself in.
After these events, Kai emerged from the hide, now a full Devil, the remains of Artificial Devil Kai controls the zombies inside the department store, floating on the roof the store with hundreds of tubes appearing from his stomach attached the zombies.
The creature is unique in the manga because it cannot be categorized as any sort of being known in particular is, in fact, an amalgamation of everything:
- Its entire structure, organs, and flesh is made out of Magic User corpses, but is not a Sorcerer because of this.
- Its technically a human, because by default Ai Coleman's body is the core of the creature, but still is just a portion of it, not the overall entity.
- It could be categorized as a Devil, because its the vessel from where Kai will emerge as a Devil, but by that logic, it would render it simply an object rather than a character.