During his youth, Storm Shadow was a student of Hard Master, his uncle and the leader of the Arashikage clan of assassins. However, his life became more complicated when the Hard Master took on a new student, the boy who would grow up to become Snake-Eyes. Angry at the way Hard Master favored his rival, Storm Shadow tried to assassinate Snake-Eyes by sprinkling poison into his tea.
Later that day, Storm Shadow witnessed what he thought was Snake-Eyes, alive, slitting Hard Master's throat with a reed. He concluded that Snake-Eyes had murdered his uncle, unaware that that their cups had been switched, meaning he himself had poisoned their master, and Snake-Eyes had been trying to perform a tracheotomy and open up the Hard Master's larynx to help him breathe.
Blind to this fact, Storm Shadow tried to kill Snake-Eyes. Snake-Eyes escaped, but not before Storm Shadow threw a shuriken at him and injured his throat, which removed his ability to speak.