This manga is about demons/devils invadeing our world and to counter this a special squad of if i remember correctly youngsters who has a demon/devil inside of themselves or if they were useing them i cant remember the only scene i remember is the main man falling down into a hole which the demons are entering our world from and he ends up getting a demon inside himself or something like that.

Tokko?

Yep, it's Tokko

I guess you can hi-jack someones idea, but you'll never understand their plan for its success.
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