Duo

Duo is a character in Mega Man 8, and also the last boss in Mega Man Battle Network 4. He is an extraterrestrial robot with the mission to eliminate the Evil Energy. In the English version, Duo can have a gentle voice one moment, and a mighty roar the next. His left hand glows to attack and absorb the Evil Energy. Strangely, his name is also the name of the last boss in the shoot-em-up Varth.