Kukai is the leader and strongest member of Team Kuu.
Tall, bald, and muscular, Kukai is the largest and most powerful member of Team Kuu. However, in spite of his great size, his facial features are usually soft and relaxed, making him look similar to a monk. Kukai wears a standard, white martial arts gi without sleeves, as well as a beaded necklace, which is actually his madogu. In his battle against Recca and his activation of his madogu, he removes his white martial gi to fight him in shirtless.
Most of the time, Kukai has a relaxed, calm attitude, and rarely ever shows any signs of extreme emotion. He is also quite laid back, as seen when he'd rather relax in the grass rather, than go to the tournament's opening ceremony. Kukai is also easy to befriend, as he quickly did so with Recca before their teams met in the ring, and stayed just as friendly with Team Hokage after the loss of Team Kuu.
In contrast, all these features vanish when his madogu has been activated. Kukai the Buddha. After his madogu has been activated, he turns into a demonic fighter who brutally attacks his enemies until they are defeated, as shown when he nearly beat Recca to death in their match. The real Kukai however is aware of his actions when in this state, and his intentions can still be pure.
He has a daughter named Misora.
Part in the Story
Ura Butou Satsujin
Three days before the final battle, the Kuu were contacted by Kagerou via a note she sent by crow. When Team Hokage was being held up by Mori's zombies, the Kuu appeared just in time to hold them back for Team Hokage to break through.
Kukai saves Domon from Kadotsu, who had just slaughtered many of the Kuu's members, including Minamio. After arriving at the closest building, they split up, with Kukai intervening in the fight between Mokuren, Mikoto, and Recca. He yells at Recca, who had been swallowed by Mokuren's giant Venus Fly Trap, to stop playing around, causing Recca to effortlessly break out of the trap. Kukai takes on Mikoto while Recca attacks Mokuren, but Mikoto quickly makes the mistake of hitting Kukai three times, causing the Buddha to come out. In a simgle smash, he completely destroys Mikoto's strongest puppet and gravely injures her. With Recca, Kukai witnesses Mokuren callously stab Mikoto when she begs him to retreat with her, and becomes enraged. However, his fists have no effect on the plant, and is quickly knocked out of the fight. After Recca emerges victorious from the battle but passes out as a result of oxygen deprivation, Kukai grabs him and escapes with Kamui, who informed them that the building would self-destruct.
Once Recca wakes up in the middle of Kukai performing CPR on him, they split ways once again, with Kukai and Kamui staying behind to fight off the zombies once again.
After the destruction of Tendou Jigoku, Kukai hosts the next Ura Butou Satsujin, with some major changes such as the banning of killing. He calls Recca to see if he would participate, since Domon and Fuuko had both turned him down, but received a similar answer.
In the anime version, Kukai posesses a madogu called Oni that transforms him after being struck three times. However in the manga, this is an innate ability that Kukai possesses. After his transformation, Kukai's muscle mass increases, he opens his eyes, and his facial features change, becoming hard, focused and with a bloodlusted look in his eyes.
Additionally, Kukai is also a powerful martial artist as seen when he easily defeated Recca in unarmed combat, even blocking Nadare with his bare hands.