In Dark Souls, the first boss encountered in the Undead Asylum is the Asylum Demon.
The Asylum Demon appears in the courtyard shortly after the player character escapes the starting cell. The encounter introduces several central mechanics: boss health bars, powerful enemy attacks, stamina management, and the importance of using the environment. A player who drops through the opening above the arena can perform a plunging attack, making the battle easier.
The Asylum Demon is a large demon wielding a hammer-like weapon and is associated with the asylum’s other demon inhabitants. It is possible to leave the first encounter without defeating it, then return later with better equipment for a rematch.
The boss is often confused with the Stray Demon, which is a later, stronger version found in the same general starting region. The Stray Demon occupies the Undead Asylum after the player returns there, but it is not the first boss fight.