Ryusenka
Would be funny if they defeat Tamamo because of her going in to heat... and the closest to her be our mc. That could get him a title like Red Brest Dragon Emperor (Issei) and White Butt Dragon Emperor (Vali). Not sure witch one would be good, but 'SunStorm Fluff Uncrowded Dragon Emperor' is best I got. The Uncrowded part could be removed after being recognised bye few stronger dragons as worthy for Dragon Emperor title, like Albion, Ddraig, Tiamat, Crom... etc. (P.S. Fluff is because he is part of Yokai faction)