Gamma

Gamma (ガンマ Ganma) is a giant peacemaker robot constructed by Dr. Light and Dr. Wily. During Gamma's construction, Dr. Wily feigned peacefulness, gaining Dr. Light's trust and assistance long enough to complete the giant robot. Dr. Wily's true intentions were to use the enormous creation as a weapon, furthering his evil plans for world domination. It is the final boss from Mega Man 3. It also appeared in the cartoon Captain N: The Game Master. Sigma took a similar form in Mega Man X3.

Trivia

 * Gamma (Γ) is the third letter of the Greek alphabet.