Metal Man is a robot master from the Mega Man series. He is the first robot-master fully designed by Dr. Wily himself.
Despite throwing blades almost impossible to doge, he's one of the easiset fights in Mega Man 2. Even the plain megabuster shots do more damage with energy to spare.
After that you get his power; the metal blade.
Which is decent, but ironically does more damage to Metal Man than any other boss...