Koutetsu Akumu (鋼鉄悪夢, Akumu Koutetsu) is a major antagonist in Naruto - Eigoukaiki. He is a Jōnin-rank shinobi from Kumogakure who possesses the rare Dark Release, the Kekkei Genkai of the Akumu Clan. After he defected from Kumogakure, he began to live in Amegakure, where he became the Guardian of the Akumu Shrine. He is considered one of the most powerful Kumogakure shinobi by the other Great Nations, even going as far as Kirigakure putting a bounty on his head. He is nicknamed the Silver Lightning (紫雷, Raikou no Gin) by the people of Kumogakure because of his speed and the colour of his kimono.