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. In The Day of Sigma, it is heard that Zero had destroyed Gamma's units, implying that Gamma was rebuilt and reactivated after Mega Man 3. This is further reinforced by the appearance of Gamma Sigma in Mega Man X5, in which Sigma's head replaces that of Gamma. This is very similar to Wily's machine replacing Gamma's head in Mega Man 3.

Trivia

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