Bass

Bass, known as Forte (フォルテ, Forute?) in Japan, is a Robot Master created by Dr. Wily to imitate Mega Man's design, along with Treble, an imitation of Rush's design. He was created sometime during or before the events of Mega Man 6, and made his debut in Mega Man 7. Bass is the prominent anti-hero of the Mega Man classic series, fighting against Mega Man to prove he is the strongest robot in existence. Although Bass and Mega Man are rivals, at times they team up to take down mutual enemies of the two. Through these team-ups with Mega Man and his friends and their plea for peace and friendship, Bass seems to become less hostile to them as time goes on. (Source: The Mega Man Knowledge Base Wikia)