狂性奴～クルセイド～

Everything changed the day after Tachikawa Kazuya died in an auto accident… or rather, he should have died. It was at the moment he was straddling between life and death, when Kazuya sealed a pact with a powerful demonic entity. He would be granted unimaginable strength, more than enough to cheat the Grim Reaper of its prize, with enough remaining to make his darkest fantazise come true. Yet the price would be “sharing” his mind and soul with the evil deal maker. Faced with the inevitable fate of oblivion, Kazuya accepted: and the Heavens lamented in sorrow.

[From an old review by Nargrakhan]