Ultraspeed Regeneration

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

As can be seen, by the name, it grants the user incredible regeneration properties, far superior to Self-Regeneration. It's considered equal or better to the Orc Disaster's Regeneration combination of Starving Ones + Self-Regeneration, which was implied to require the destruction of the entire body on an atomic level to beat.

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

Trivia

 * During the Clayman vs. Shion Combat, at the Walpurgis Banquet, Clayman quickly regenerates after receiving his first attack, so Rimuru asserts that his regenerative power exceeds that of (Orc Lord / Orc Disaster) Geld I, an extremely capable individual for Survive thanks to its Self-Regeneration ability enhanced with Starving Ones, It is suspected that he had this Skill or at least one variant.