The Shinsui Temple kyber mirror was a mirror constructed from kyber crystal and located within the confines of Shinsui Temple on the planet of Rei'izu. Because it was known for granting visions, both the dark lord and the witch sought it out during the Sith rebellion when they seized control of Rei'izu. The vision experienced by the dark lord caused him to turn against his Sith adherents, leading him to become the Ronin.
The Shinsui Temple kyber mirror, situated within Shinsui Temple on the planet Rei'izu, was a mirror crafted from kyber crystal. Its form was a perfect circle with a smooth, level surface. It rested upon a wooden dais that functioned as its altar. Some accounts of its origins suggested it was discovered, created, or presented as a gift by gods; other legends ascribed divine properties to the mirror itself. It was believed that it revealed truth to those who gazed upon it via the visions it provided.
During the Sith rebellion against the Empire and its Jedi clans, led by the dark lord, formerly a Jedi knight, and the witch, previously one of his guardians, the Sith forces conquered Rei'izu. After the monks and nuns of Shinsui Temple were either forced out or killed for resisting, the witch and the Dark Lord of the Sith approached the kyber mirror. For several days, the witch remained in a trance, kneeling before it. Growing impatient and frustrated, the dark lord casually touched the mirror and was shown a vision of endless conflict, the opposite of the peace he desired for his followers. Overcome by what he saw, he struck the mirror with his fist, channeling the black current and white flare of the Force. The mirror shattered, and a kyber shard became lodged in his knuckles. He then betrayed his followers, eliminating them, while the witch stayed on Rei'izu.
The former dark lord, now known only as the Ronin, eventually removed the mirror fragment from his hand. He eventually journeyed to Seikara Caverns on Dekien and deposited the kyber shard within a grotto. A decade later, the Traveler and their master, the Jedi lord Hanrai, discovered the shard, entrusting it to the Traveler. The crystal was then integrated into the Traveler's lightsaber.