Denji is a teenager who lives his life as a Devil Hunter.

Aiming to pay off the debt he inherited from his father, he starts hunting devils for the yakuza with his buddy Pochita, a "Chainsaw Devil", while living a tragically poor life.

Just when things seem like they couldn't get any worse, Denji gets betrayed and killed by the yakuza. As Denji starts passing out, he hears someone calling from inside his head...
Every blood of drop that 
goes down is a nightmare
Jedes Mal, wenn ich Blut trinke,
kommt mein Albtraum wieder.
À chaque goutte de sang gobée
Le cauchemar ressuscité
Toda vez que tomo sangue,
o pesadelo retorna