His superiors were not pleased with his results as a salesman. Down on his luck and constantly under pressure for results, he volunteered to dress up and perform like a superhero at a carnival thrown for a top customer in their department store. He had hoped it would be a chance to prove his value as a salesman. When he grabbed the attention of all in attendance, something clicked in him. Skullomania now realised his fate to be a superhero.
...
No, seriously, that's his official backstory. Word for word.
Skullomania is perhaps one of the most messed up characters in Capcom history, and that is saying a lot. He is an salaryman who put on a sentai hero suit that was painted to look like a skeleton, and he FIGHTS CRIME. His real name is Saburo Nishikoyama and he has a pet dog called Pochiro Kun. Whether the dog also fights crime is unknown.
It's hard to determine exactly what kinds of powers Skullomania has or has not. He is a martial artist, but can either be an utter joke or secretly very good (the EX series has even less information about this sort of thing than Street Fighter III). He does at least have a few moves that contain flashy pyrotechnic effects. He is known to throw himself head-first at enemies and calls all his moves "Skullo-" something.