Alter Man was (or may be is... if rumors are true and he escaped from the curse of Athena) the evilest super-hero on Earth, leader of Evil Leage of Evil Super Heroes.
After being hit by a nuclear weapon he was bitten by a radioactive mosquito. After two days, a evil black hole exploded, transfering him its evil powers of doom. That was not all, many people say he came from another planet before it was destroyed by a dying star. More over he was abducted by evil aliens who gave him more evil super powers. After defeating his good twin, he became "ALTER MAN!!!" to destroy the whole Earth.
He just said: "I have too many evil powers. I do not want but I HAVE TO use them, so I will destroy Earth".
Barletta paid him enough money to built an secret lair after Alter man accepted to destroy the Continent. One of the survivors was Dark Stallion.
Once a day he separated the horse spirit from Dark Stallion. He thought he had won, but he did not realized that Bolt was a really wild horse when it had no more human side anymore, and it easily destroyed the whole lair of Alter Man.
Alter Man has lots of evil fiendish friends, they all members of ELESH. However, he is so devilish he was planning to get rid of them ally to become the only super villain and leader of Earth.
He was destroyed (or may be not) by the goddess Athena. See Dark Stallion.