Devil because I can basically use my imagination to create crazy spells and effects

Fuck I am have to go with devil they arguely have the best potential in the show

@The arcmage Small correction, it is the Gods and Dragons that have the most potential, the universe is kind of named in relation to them.

The dragons yes have strong potential but there kind is little left it's the reason tanin became a devil unless they retcon that and there's little information on gods in dxd but gods shouldn't be counted since well there gods and there powers are random

There are not a few dragons left, Tannin and his group are a type of Dragon that only eats a certain food that grows in the forests of the underworld, so he made a deal with Mephisto.