Train was born in Konoha to the uchiha clan. He showed promise from a young age and gained the attention of several outside villages. When he was 5 years old, rogue ninja broke into his house hold killed his entire family and kidnapped him. They took him into a cave where they trained him for years to be an assassin, they taught him to always be on his guard and to never form bonds with anyone else. When he was 12 years old, he was wandering around the forest outside he met a girl named Saya. They slowly started to talk and later even became friends. Saya had done what everyone else had failed to do. She had made him feel
Eventually the rogue ninja started to notice something had changed in young Train. They were curious so they followed him out of the cave one day and they saw him meet Saya. They immediately made plans to eliminate her, the following day when he went outside to meet Saya he found her dead.
Train immediately guessed what had happened and he went back into the cave and in a fit of rage slaughtered every single rogue ninja. When he finally came back to his senses he was back to being detached and emotionless. As he was about to leave he heard a strange sound, it was one of the rogue ninja laughing! The rogue ninja seemed to be alive but on the brink of death, when Train walks up to him and demands to know what is so funny the rogue ninja keeps laughing and says something train will never forget. "Your training is complete"
the rogue ninja then died. Train then left the cave and became a professional assassin where he offers his services to the man with the highest price...