Multiple choice general knowledge Cerberus is the three headed dog of which Greek God? Zeus Hephaestus Hades Poseidon Reveal answer Fill a bubble to check yourself C Correct answer Explanation Cerberus was the three-headed dog guarding the entrance to the Underworld, which was ruled by Hades. Hercules' final labor (12th) was to capture Cerberus. Zeus ruled the heavens, Hephaestus was the god of fire/forge, and Poseidon ruled the seas.