|Occupation||Part time job at the Kasukabe Clinic.|
Has black hair, which covers his left eye, skinny complexion and a constant apathetic look.
Ai lived with his grandfather all his life, looking at the Magic Users that invaded Hole with respect and hate, wishing to become one, but knowing the differences in their physiologists, he became the assistant of Prof. Kasukabe in his clinic in hopes to investigate the possibilities of becoming one by a surgical procedure, helping him in collect bodies or sorcerers killed by the Militia and working in his own research, having Jars of hair and bones of magic users to study them.
Years later, Ai would find the opportunity to become a Magic User, jumping in The lake of Refuse to rescue the body of a sorcerer trowed in there by the militia to die, he was exposed to the Lake toxins and his body was invaded by a sinister entity. Disfigured and at the verge of death, Kasukage fulfilled his dying wish and used Ai's investigation notes to surgically save his life with the bodies of 8 Magic Users, after a long and dangerous surgery, Ai survived and spent months to finally be able to go outside again, claiming that he has "Become one with the city".
Ai found two Magic Users who came to practice in Hole, wishing to be sent to their realm, approached the sorcerers claiming that he was one of them, unable to produce smoke to prove it, he was beaten to death and left with his face in a storm drain. He was buried and the entity inside him bring him back to life years later, with a grown-up body and the ability to regrow his head 9 times, becoming his pawn and possessed by it for years.
Ai, now a full grown adult, woke up in an apartment, with money and all the needs to live in the Magic Users realm covered, he found a gas mask in his table and with that, decided to cast out his past and renamed himself Aikawa.
Aikawa became a split personality of Ai after the long and recurring nightmares of people dying, this make Ai lost himself willing to overcome these visions to live a proper life, rendering him as nothing more than a headless ghost in his own mind, leaving the control of his body to two different personalities for the years to come.
He would appear in visions and nightmares to both Aikawa and Kaiman, trying to comunicate with them about the atrocities their actions unleashed, for Aikawa, a dreadful reminder of how his body is used to slaughter countless of innocents, to Kaiman, the horrifying truth about his past self.
Thanks to the shock that Aikawa suffered by Prof. Kasukabe question about if he was Ai, the spirit of Ai regained control of his body by growing his former, rotten head and crawled to Kai's laboratory to fuse himself with a suit made of Magic Users flesh.
He appeared once again in the Central Department Store (now morphed into a physical representacion of his and hole's mind and body) to posses "The Second Kaiman" to be able to kill one of the heads of Devil Kai with the Store's Kitchen Knife, tagging with Curse Risu, and apologizing with him for not been able to save him from The Cross-Eyes boss (explaining with this, that Ai took the position as Aikawa, now both as one personality again). Ai explained all his backstory to him and a severely wounded Kasukabe while heading to the battle against Hole.
Once they arrive to the room where the En mushroom clones finally killed Devil Kai, Ai used the Store's Kitchen Knife to cut the morbid deformed head of his evil persona, triggering the final resurrection and with it, the last remaining head, in that moment Ai knew that with no other heads to regrow except his own, then he abandoned Kaima's body and his old, rotten and disfigured head appeared from the neck of Kai's corpse, with his final resolution, believing this would be the very end of all, he asked Risu to kill him using the Knife so Hole would no longer exist. Hesitant about the idea of kill his only friend, Ai/Aikawa told him that if he have to die, he would prefer to die at his hands, after a sad goodbye between them, Risu sliced Ai's head from the neck of Devil Kai. Chapter 146
The 8 Ball on his hat was possibly foreshadowing to how many Magic Users were used on him.