Defense Devil- Kucabara
Mephisto Bart Kucabara is a devil lawyer. In order to return to the demon world that he was exiled from he needs to collect enough Dark Matter. To do so he creates a plan to claim the Dark Matter from the souls of sinners sentenced to hell. Prove the soul's innocence and the Dark Matter becomes his.
"sign a contrac with me, and you can live again"
you have not read the manga yet?
c'mon read it it's great!