Beware major plot spoilers. Read at your own risk.
Aikawa has short black spiky hair and usually wears a metal baseball cap backward. He is always wearing a black hoodie, white pants, and combat boots.
He sometimes wears a black gas-mask that covers his entire face.
Aikawa has the same personality as Kaiman, arrogant and lazy, stubborn towards everything he doesn't want to do or answer. Risu is the only person he cares about. This doesn't stop him from helping the people in need (most of the time saving the weak or helpless people when they are bullied of tormented by Magic Users) and asking them later to thank him with food most of the time.
Aikawa lived as a third rank Magic User. Unable to produce enough smoke to use magic, he went to the South Zagan Magical Training School to learn how to use magic and produce more smoke. There he met Risu, and teamed up with him to get rid of an abusive teacher. Afterward, they became close friends and partners (at least by word).
Living a happy life with no worries while stealing food from the school's cafeteria and lazing around, he knew from the beginning that his body was inhabited by a sinister entity. He was aware this entity possessed him for long periods as it killed Magic Users. In exchange for his silent cooperation, this entity provided Aikawa with money and a residence. Too scared to acknowledge the truth, Aikawa favored blissful ignorance to maintain his current lifestyle. However, when Risu told Aikawa about his magic, the entity possessed Aikawa's body to kill Risu to gain the latter's power.
Aikawa woke up near the flayed Kawajiri, who took his body and teleported with him far from the Hostel were En fought Kaiman and Nikaido. Believing he was someone else, he woke up a month after and took care of Kawajiri for a few days, living in an abandoned house in Abaddon near where he woke up.
There the ex-Devil asked if he was Kaiman, Nikaido's friend. Avoiding the conversation, he simply replied "I'm Aikawa, I don't know that guy", and accidentally was teleported with Kawajiri once again (by graving his arm) to En's Mansion, where he met a weakened and infected Nikaido (her resistance to regrow her contract with En pushed her body to the limit, such that even Noi couldn't heal her).
She politely asked him to remove his mask, because his body shape and voice were the same as Kaiman's. He, not wanting to get involved much more, denied her request. Nikaido fought him in her weakened state to force him to take his mask off. Aikawa, fulfilling her wish in the end, let her see his face before saying "Goodbye" and jumping through a window to escape the Mansion.
He was once again possessed by the entity and woke up weeks later to discover that En was killed by The Cross-Eyes Boss. The En family was destroyed, and the Cross-Eyes had taken over the Mansion. Not caring for any of that, he encountered an ex-classmate who was being bullied by other Magic-Users; Aikawa quickly took them down and saved him. He told Aikawa about the new school of magic in the city, founded by En after he had closed the Zagan School for being a place infested by the Cross-Eyes.
Wishing to enroll there, his classmate asked him about Risu, not knowing anything about him since he woke up, he headed to Risu's apartment to find him possessed by Curse. There, he took care of his friend until he felt better, and resumed his routine going to school, with Risu tailing to confront him about why or who killed him, believing that his friend told a Cross-Eyes about his type of magic. Labeling him as a traitor, Aikawa could not give a proper answer to Risu, transforming into Curse and storming out of his sight. Heading to En's Mansion (knowing that Risu went to confront the Cross-Eyes), he was found by a gender-bent Nikaido (masquerading as members of the organization to sneak into the building to retrieve an old book about time magic). Aikawa once again firmly stated that he wasn't and didn't know Kaiman, to Nikaido disbelieve. He saved Risu and entrusted him to her and Kawajiri, knowing that the entity would emerge once again to take Natsuki magic for itself (Accidentally eavesdropping a conversation between Tetsujo and Dokuga about her newfound power. The entity listened too). Thus, exploding his neck and letting a new head take its place.
The entity took control of him and started a global scale killing spree of Magic Users with The Cross-Eyes. He regained control of his body in Tanba's restaurant. He shouted Fukuyama to turn him into a meat bag, later the magic was dispelled and was imprisoned by the Cross-Eyes officers after realizing he "Wasn't" the boss. He remained in one of the Mansion torture chambers with a straitjacket until he was found by Prof. Kasukabe and Jonson. After the professor asked if he was Ai, the hidden personality beneath his mind took over his body, replacing the now dangling head of Aikawa with a rotten new head. The new persona in his body crawled to a laboratory with many heads of Magic Users staked in the walls, amazed with the possibility to continued his research, Kasukabe told him about help in any way he could, Ai wounded the professor and Jonson. When the entity gave the control of his body once again, and acknowledge the fact that was just a puppet for Hole's control, looking at Natsuki disembodied head, Aikawa tried to commit suicide by stabbing himself over and over (and with this, kill "Hole" in the process). Still, Hole took control of him again and merged with an estrange bodysuit made of Magic-Users flesh.
He appeared once again in the Central Department Store (now morphed into a physical representation of his and hole's mind and body) to possess "The Second Kaiman" 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 being able to save him from The Cross-Eyes boss (explaining with this, that Aikawa and Ai Coleman are once again a single identity). Ai/Aikawa explained all his backstory to him and a severely wounded Kasukabe while heading to the battle against Hole.
Once En killed Devil Kai using his mushrooms, they met with the other main characters inside the chamber of coffins from where all the personalities of Aikawa and Hole got resurrecte. He slashes the head of Kai with the knife once again and found out that the last remaining head was his own. Leaving Kaiman's body, Ai/kawa spirit got inside Ai's old rotten head, explaining that to kill Hole once and for all, Risu had to use the Knife to kill him. Hesitant about the idea of killing his only friend, Ai/Aikawa told him that if he has 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
- Usually really hungry.
- Doesn't show it but is very worried about Risu all the time. The biggest example could be making sure that he's kept away from the Cross-eyes.
- Aikawa, along with Kaiman, is one of Ai Coleman's alter egos, and he's very much aware of Kai's existence to his horror.
- Even with his volatile and carefree personality, Aikawa is not as violent as Kaiman. He avoids conflict and even killing anyone, if not necessary, and taking care of Asu even if he didn't know him making him one of the less violent characters of the series. Interestingly, in chapter 23, it is stated that Ebisu's magic turns the cursed person into a "Super Badass Lizard". This might suggest that Kaiman's aggression is a side effect of being hexed by Ebisu's magic, which could make sense; when Noi was turned into a lizard, she became far more violent and lost her memories afterward. Similar to what happened to Kaiman, but this is only speculation.
- Aikawa's name (会川) uses the kanji (会) which can be pronounced both as "ai" or "kai" and means meeting or a party of people, it also uses the kanji Kawa (川) meaning stream or river