Ultraspeed Regeneration

Ultraspeed Regeneration (超速再生) is an Extra Skill that is the enhanced version of Self-Regeneration.

Rimuru had obtained the skill after his Unique Skill Great Sage combined his Intrinsic Skills as a Slime, Absorb, Dissolve and Self-Regeneration, together with the Mimicry of his Predator using his recently acquired Degenerate. Shion had also obtained it as an Intrinsic Skill after her revival following the invasion of Falmuth Kingdom.

Abilities
It grants the user incredible regenerative properties far superior to those afforded by Self-Regeneration. Any injury and damage that doesn't instantaneously kill the user can be regenerated very quickly.

However, the regeneration is blocked when a wound has been caused by Spiritrons, for example via Disintegration. Also, damage done to the Spiritual Body can just bypass the regeneration itself altogether.