The Third Eyed King was a ruler with whom Thanos attempted to ally himself.
Biography[]
Desiring to ally with the Third Eyed King, Thanos sent his adopted daughter, Gamora, to attempt to forcibly negotiate with him. When negotiations soured, Gamora decapitated the Third Eyed King and brought his head back to Thanos, claiming that the Third Eyed King would now eternally be loyal to Thanos in death.[1]