|Branch of Sin||Decimating Frenzy|
|Affiliations||Forgeries, 1st Unit|
|Manga debut||Chapter 31|
|Anime debut||OVA: Red Knife Wielder|
Ikazuchi Akatsuki is a Complete Forgery, formerly assigned to the First Unit.
Akatsuki has very long, brown hair that reaches down to his lower back. His hair is shaved at the sides and he keeps it in a ponytail. He has a metal mouth mask that points out at the height of his chin. He doesn't wear a shirt, but does wear two bands over his elbows, as well as black pants with a belt of rope.
After the great earthquake Ikazuchi was one of the many thugs, who live in the slums, while doing criminal activities. Ikazuchi had then stated that Senji who, at the time was a police officer, and his team were not ordinary, and had sent a challenge to Senji, via letter, to fight him. This however did not happen as instead his fellow officers from his team decided to fight without him, but without Senji, Ikazuchi and the other gang members were able to kill the police officers.
He is first seen with the other members of the first unit forgeries, stopping Ganta, Azami, and Shiro from getting to the control device. He as well as the rest of the first unit then charges to Ganta, but are stopped by Minatsuki Takami's branch of sin. It is then revealed that she is not alone as Chaplin Sukegawa, Senji Kiyomasa, and Idaki Hitara are revealed. The deadmen then tries to take on the forgeries but are easily overpowered. This however changes as after Ganta leaves the deadmen are able to separate the first unit forgeries, with Senji taking on Ikazuchi.
Ikazuchi while fighting Senji then tells Senji that it is a small world, meaning that he knew Senji from his past. Ikazuchi then reveals his poison, which is revealed that by stinging himself he is able to increase his strength, which he uses to clear a space for them to fight. He is then attacked by Senji who is now frustrated at the unknown relationship he has with Ikazuchi. Ikazuchi then breaks Senji's branch of sin, and tells him that he was the one who killed his teammates. Senji then asks why while battling Ikazuchi, to which Ikazuchi explains that he was simply protecting his paradise, as the world after the earthquake had become so.
Ikazuchi keeps doping his muscles, as he continues to fight Senji. Senji then points out that he can not power up his tendons, and aims for them, but this proves to be false as Ikazuchi is able to power his tendons, and proceeds to use his doping on his legs, jumping up and caving the entire ceiling on Senji. Ikazuchi then looks on to Senji wondering if he had given up. This however proves to be wrong as Senji gets up, even with a lack of blood. He then watches as Senji cuts himself in an x shape across his torso allowing him to create a heavy blade with his branch of sin. Ikazuchi then uses his doping one last time, to increase all of his muscles, and they both charge at each other. After the clash Ikazuchi is killed, as Senji had slash through his shoulder to his lower torso.
Branch of Sin: Ikazuchi is a Complete Forgery, so he has the ability to freely control his blood out of his body.
Branch of Sin: Rari Ranshin (乱离乱身, Rari Ranshin, lit. Decimating Frenzy): Rari Ranshin allows him to create scorpion tail-like tentacles that inject himself with blood. This causes his arms or legs to enlarge and become extremely muscular, like some kind of doping; he gains superhuman strength, powerful enough to strengthen his muscles and tendons and shatter Senji's normal Crow Claw blade. Ikazuchi doesn't use his Branch of Sin as a main weapon, but rather his enlarged body.
- Asōgi (阿僧祗): Ikazuchi enlarges his legs to become incredibly muscular, that have enough power to jump several feet in the air.
- Kōkasha: Ikazuchi injects himself in the shoulders and uses them to body-check his opponent.
- Nayuta: Ikazuchi enlarges his whole body. However, he was defeated by Senji before he could unleash its full potential.
|1st Unit||Shishito Madoka · Ikazuchi Akatsuki · Uzume Sumeragi · Ichi and Hajime Mikawa|