Naruto Bael was born a low-class devil before the Great Devil War ever was a thing. Realizing how the devil-class system subjugated devils of lower class, Naruto will represent his origins as he rises and expose the corrupted system that he lives in, and he'll do it without the high-class devils even realizing it. Power of Destruction Naruto! Mass character crossover.

For eons he watched, doing the duty bestowed upon him and keeping up the order. Until one single mistake caused everything to spiral out of control. A mistake he made, one he shouldn't have but didn't regret. And now, now he's paying the price though he's ready to face whatever is sent his way. [Multi X-over]

Naruto Gremory was Rias' twin brother who disappeared in order to gain what he could not get in the Underworld. Years later he returns to help out with the problems surrounding Kuoh and Rias herself only to find out that there is more about himself than one would've thought.