During the Sith rebellion against the Empire and its Jedi clans, the Sith captured Rei'izu. The rebellion was led by a former Jedi knight who became a Dark Lord of the Sith, later known only as the Ronin, and a witch who had been a guardian alongside him. Their capture of the Imperial homeworld proved to the Empire that the Sith were a genuine threat, leading formerly feuding lords to band together.
The dark lord and the witch entered the Shinsui Temple together, and after expelling the nuns and monks who were willing to leave and killing those who would not, they approached the legendary kyber mirror of Shinsui Temple. The witch knelt before the mirror and began praying, entering a trance. After multiple days passed, the dark lord grew frustrated; without intent, he idly touched the mirror. The vision of unending war and resulting guilt for his own actions were overwhelming, and he struck the mirror with his fist and with the black current and white flare of the Force.