For the Silver, Bronze and Modern Age version see: Metallo

Origin

Scientist George Grant discovered a super-strength serum and created a suit of armor mad of "the most powerful metal on Earth."

Major Story Arcs

He robbed a mail train in his first successful criminal outing, with the police confusing him with Superman, that attracted the attention of the man of steel. After their first encounter Grant managed to kidnap Lois Lane.

Him and Superman would later face each other, with Metalo proving to be the Kryptonian's physical equal. After a battle which broke mountains Superman managed to make Metalo trip into a volcano, thinking the villain dead he left with Ms. Lane, but Grant actually survived by falling on top of a rock, he swore revenge but It took decades to fulfill It.

Years later he would challenge Superman once again. His suit's alloy having being improved and the power of the strength serum being doubled, he created a ray weapon which could weaken Superman to being weaker than he was in the golden age. Superman managed to restore his full power through a regiment of intensive training and defeated Grant for the last time.