The Protector is an android created by the Masters of the Black Stars to protect them from any intruders. The masters anticipated that one day the slaves they created to run their machines would try to rebel. The Protector was created to keep the peace by crushing any rebellion.
He flies in a giant ball to the place of conflict, then jumps out and attacks. He shoots beams from his hand. Thor's hammer bounces off of his chest, but when Thor strikes him solidly in the head, the Protector is thrown back and explodes.
The Protector was created by Gerry Conway and John Buscema in 1974 and first appeared in Thor # 219.