Ouroboros Stone

Ouroboros Stones are objects in Xenoblade Chronicles 3. They are the catalyst of turning s with aptitude into Ouroboros.

Description
Ouroboros Stones are egg-shaped stones with green glowing lines running throughout. When opened, there is a metallic wired button, and when pressed, it transforms up to six humans with aptitude into Ouroboros, effectively freeing them from their Flame Clocks in the process if they are bound to one.

Story
Guernica and his squad,, , and Heewa are trying to transport one to the City when they came under attack by both Keves and Agnus, but all of Guernica's squad mates are killed, leaving Guernica to defend the Stone alone. After stopping the fight between Noah and Mio's parties, Guernica entrusts the Ouroboros Stone to them before being impaled by D through the chest with a stalactite-like projectile. Guernica then activates the Ouroboros Stone as a last resort to fight him off, turning the party into Ouroboros in the process and freeing them from their Flame Clocks.

Lore

 * The Ouroboros Stones were created through Nia's Core Crystal and her key to Origin.