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An Anima crystone is a stone shown in the reveal of Xenoblade Genesis. It amplifies a Vesselai's power over Anima. "Anima crystone" is the full term the trailer narration uses; the Japanese term is アニマ晶石, literally an Anima crystal-stone. Coverage often shortens it to "crystone", and this wiki does the same after the first mention. The details below come from the reveal trailer and reporting on it rather than Nintendo's product pages, so they should be read as preliminary.

Function

A crystone amplifies its bearer's power over Anima. Beyond boosting that power, it also records its bearer's thoughts, actions, and life, which gives it a role that is both practical and personal. The narration frames this second function as the more important one: every part of a student's life at Leukos, academic work included, is described as bound up with the stone.

Use in Weapons

Crystones are set into weapons such as swords. The reveal shows a blade being given to the protagonist and then imbued with a crystone, so the stone appears to be added to a weapon rather than built into it from the start. Since the warriors who wield Anima fight with such weapons, the crystone is tied closely to how a Vesselai fights.

What Is Not Yet Known

Whether the crystone functions as a gameplay or upgrade system, and how crystones are obtained, has not been detailed. The reveal shows them only in the context of the world's lore, not as an explained mechanic. These details are deferred until Nintendo shares more.