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Regeneration is a trait where a creature heals at a supernaturally fast rate and/or with supernaturally high levels of efficiency. A creature capable of regeneration can heal from massive amounts of damage, potentially recovering from even such extreme injuries as as severed limbs or removed organs.

In Dungeons & Dragons 3rd Edition, regeneration is broken into two traits; regeneration proper, and Fast Healing, with the main difference being that the former can innately replace sundered limbs.