Yoki

Yōki (妖気, Demon Energy) is the energy of a Yoma. When a Claymore is created she assimilates the Yoma Yoki. The claymore used certain amount of Yoki to use special skills like increasing their strength and speed. Many Claymore used their yoki to make some special moves such as Irene's Flash sword.

Release Levels

 * 10% release: Eyes change from silver to gold.
 * 30% release: Facial distortion.
 * 50% release: Whole body distorts.
 * 80% release: Theoretical limit, reversion to human form difficult, if not impossible.
 * 100% release: Full awakening.

Known Yoki moves

 * All Claymores special strength and speed
 * All Awakened Beings abilities
 * Irene's Flash Sword
 * Helen's Extension of extremities
 * Miria's Phantom Images (After the 7 year time-skip, Yoki isn't required any longer for this move)
 * Deneve's Regeneration
 * Ophelia's Rippling sword
 * Jean's Rotating arm
 * Undine's strength and muscles

However, it is unknown whether Rachel, Teresa, Galatea and Tabitha's exceptional Yoki reading ability is caused by their Yoki powers