Sean Watanabe was trained in the martial arts by his father Yuji. In competition Sean always seemed to know his opponent's next move.
He joined the military and became a member of the Navy SEAL's. He was given the nickname of Brass for taking on the tough jobs.
After he ended his military service, Sean met a woman named Theresa, whom he planned to marry. However, they were near Avengers Mansion, which was attacked by the Mandarin during the 'Acts of Vengeance' conspiracy. Theresa fled into the street during the confusion and was struck by a car. Angry, Sean vowed he would go after all responsible. He started by attacking the Mandarin's operations in Chinatown.
Deathwatch sent his men looking for all allies of Dan Ketch and the Ghost Rider. Sean's father Yuji was one of those attacked. Sean's sister was abducted and Jack D'Auria was wounded. Sean tracked the kidnappers to Cypress Hills Cemetery, where he encountered Wolverine and Ghost Rider (Dan Ketch). The three joined forces to save Sean's sister and Jack.
Powers and Abilities
Sean Watanabe is a depowered mutant, in peak physical and mental condition.
Skilled in the martial arts and also in the tactics (tactical ambushes, sniper assaults, close-quarters combat, underwater demolition, combat-swimming attack, close air support, naval gunfire support, raids, hydrographic reconnaissance) and weapons used by the Navy SEAL's (explosive, scuba diving, land-warfare).