Dr. Brusiloff was a man working in a hospital during WW 2, in a city that was being bombed by Luftwaffe. When one of the bombs fell right in to the room (filled with chemicals) where Brusiloff was, the explosion caused the chemicals to act mysteriously, and changed Brusiloff to...Blackout! Minutes after the change, he swore to fight against tyranny with his new powers.
And he began to do so immediately! He crashed planes, punched nazis, humiliated & pasted Heinrich Himmler and walked out of it alive!
Then he fell in to public domain, and he hasn`t been seen since.
Blackout could emit dense, black smoke and fly. He was also in a great physical shape.