Asylum Demon

The Asylum Demon is a boss in Dark Souls.

Location
It is found in the Undead Asylum. He will attack the player in the room immediately after the first Bonfire.

Butt Slam
The Asylum Demon flies up, pauses, and then allows itself to fall, dealing massive damage if it hits. Very easy to dodge, as it is well telegraphed.

Hammer Drive
Used by the Demon when the player is standing right in front of it. Impossible to dodge if standing in front of it.

Hammer Swing
A horizontal swing of the Asylum Demon's hammer. Has poor tracking, and is easy to avoid.

Hammer Backswing
Used when the player is side-stepping to it's right. Can be dodged by rolling at the last second.

Hammer Scoop
Used when the player is side-stepping to it's left. Once again, rolling at the last second allows the player to dodge it.

Hammer Smash
A downward smash. Has a large range, but is fairly easy to avoid.

Leaping Hammer Smash
Used when the player is far away from the Demon. Before attacking, the Asylum Demon will flutter it's wings. Easy to dodge.

Double Hammer Swing
A combo of Hammer Swings. It has little better tracking than it's predecessor, however, it may be followed up with a Hammer Smash attack.

Drops
Defeating the Asylum Demon before picking up the player's class weapon will grant a Demon's Great Hammer. The Big Pilgrim's Key the Asylum Demon would drop otherwise is given by Oscar in this case.

Before Weapon
It is possible for the player to simply run past the Asylum Demon upon their first encounter with it. Otherwise, the fight will be long and arduous--unless Black Firebombs were chosen as the starting gift.

Melee
Fighting the Asylum Demon without firebombs is an endurance challenge. Constantly avoiding the Demon's swings while chipping away at its health is a lengthy process. Standing behind him and retreating when he does his slamming attack are safe choices.

http://www.youtube.com/watch?v=nQXtMtBWGYw

Firebombs
A reliable way to defeat the demon is by selecting the set of 10 Black Firebombs as a starting gift and being sure to lock on before throwing. Five of them will eliminate the Asylum Demon.

After Weapon
Head to the second floor and perform a diving attack on the boss--he will knock you down if you take too long--then circle around him to his left (your right) to avoid his club smashes. Remember to roll sideways or backwards when necessary and never use the backstep.

If you flee from the fight on the initial encounter with the Asylum Demon and continue to make your way through the area you will eventually be able to re-enter the room at a point above him, allowing you to perform a falling attack for a large amount of damage to start the fight. This significantly eases and shortens the fight. If you choose not to attack him immediately, The asylum demon will perform a jump and strike the platform you are standing on, resulting in a large amount of damage and you falling to the ground in front of this imposing boss.

Sorcerer:Wait for an opening and fire a Soul Arrow. Pyromancer: Wait for an opening and lob fireballs - they're just as effective as Black Firebombs not more so and four or five will kill him. Everyone else: Wait for an opening and sneak as many attacks in as possible.