Attucka

Attucka was a Mongol warrior rendered immortal by Tamerkhan. He was mutated to be able to breathe underwater and having four hands. He survived from the 1220s to the 1960s, killed in combat by Aquaman. 
 
Unlike Liat and Tamerkhan, Attucka was hostile to Aquaboy and threatened to kill him on several occassions.