He was presumed killed when fighting Iron Man during the first Armor Wars when his titanium armor had caught fire and he plunged into a frozen-over lake.
During the second Armor Wars, Tony briefly battled what he believed to be the Gremlin's ghost (in the form of his Titanium Man armor). The Titanium Man taunts him and vows revenge against him. Iron Man confesses to being responsible for Gremlin’s death. But at that moment, the truth behind the farce is revealed. It is not the ghost of the Gremlin/Titanium Man that Tony is facing, but rather it is the Living Laser.
Superhuman genius, about equal to Tony Stark. His Titanium Man armor had superhuman strength, flight, internal energy weapons, life-support and was durable enough to withstand hits from light anti-tank weapons.