User blog comment:Ahomeschoolingroudon/Season 5 Early Hints/@comment-25968390-20151028174201/@comment-25968390-20151028213958

It was obvious, but only because there was an undone fight on the DEATH BATTLE Fanon Wiki. Anyways, I suppose single character guesses don't count, but just in case:

Eldio (Wonderful World) X M. Bison/Vega? Both use psychic abilities and are bad guys.