Double

Double (ダブル) was a supporting character in Mega Man X4, as well as an antagonist. He quickly befriended X during his mission, but as X began infiltrating the Final Weapon, Double revealed his true purpose; a spy sent by Sigma to infiltrate the Maverick Hunters. After slaughtering some Maverick Hunters in their headquarters, Double went after X inside the Final Weapon, and confronted him. He lost, and was destroyed.

As his name suggests, Double has two forms: the first is a short, overweight amicable form, but his second and true form is a much taller, thinner and stronger battle-ready Reploid, with sabers within the top of his hands and a gelatin-like substance is present in his body. His name is also believed by some to signify that he is a double agent. Double's weakness is, ironically, the Double Cyclone.

Double has a short appearance in the opening scene of Mega Man X5.

Trivia

 * Double's sword-arm and evil grin upon showing his true nature is similar to that of another double agent/traitor that served with X and Zero later on.