Vesdar

Vesdar is an NPC involved the quest Lazarus Pit who has been in hiding for decades after Dullahan (who is mentioned in greater detail in The Headless Hunt) "lost his head and went crazy". He has the ability to stay alive and youthful almost forever due to his supply of healing water. He tests the player by requesting 16 Rotten Skin, which can only be obtained by killing Rejuvenated Corpses, in order to see if they are capable of dealing with the obstacles which are present at the pool of healing water at the Lazarus Pit.

Location
Note: you must solve a puzzle in order to enter his "home"