Silver Samurai was a mutant rebel in his homeland of Japan. Alongside Sunfire, he stood as the last line of defense against the hordes of Apocalypse. During Sunfire's tragic, and diversionary, battle with Apocalypse and Nemesis, Samurai led the surviving people of Japan to safety. He and his wife, Viper, fought their way from the island of Japan through hordes of Apocalypse's Infinites. Tragically, Viper was killed saving Samurai's life. Never able to forgive himself for the death of his wife, Samurai threw himself into fighting Apocalypse's forces in Asia.
After Apocalypse was destroyed by Magneto, Samurai discovered that Sunfire was actually alive. Samurai made his way to America and reunited with Sunfire by joining Magneto's cause. Unknown to the X-Men, he also delivered a top-secret weapon to Magneto. Samurai also has a long-standing feud with Wolverine. What caused this has yet to be revealed.
It is clear Samurai sacrificed much in the service of Japan and now is one of Magneto's bravest warriors. But only the stoic Silver Samurai knows whether he is truly brave or does in fact wish to join his beloved Viper in death.