Looking at the graphics more, there are actually sprites from Martial Champion (as people believed to be a prototype, others say a bootleg that barely started, personally both) yet... They do not resemble the sprites from that game due to their larger size. They do resemble the PC Engine version but those are smaller than this version...

Out of them could make out Jin, Titi/Chaos, Salamander, Hoi (Beggar So), Bobby and there are a couple more. Sadly palettes are missing... Jin is the closest and here's an example.

Oh and the third fighter that's actually in the "game"? He's a mess to arrange in terms of the tiles and doesn't help using more than one palette. Like it was just shoved there.