In Dark Souls for the PS3 and Xbox 360, the Demon’s Great Hammer is a giant hammer that you can get early in the game from the Asylum Demon, which is the first boss you find at the very beginning of the game. The Demon’s Great Hammer has 138 attack power, but requires 46 strength to wield effectively.
You fight the Asylum Demon before you get your starting weapon, so the only thing you have to fight the demon with is a sheath to a sword, which isn’t going to do much damage. There is a way to beat this demon however, if you choose the right Gift when creating your character.
When you are creating your character, choose the Black Firebombs as your Gift. This will give you ten Black Firebombs to start off with, and it only takes about five or six to kill the Asylum Demon and get your Demon’s Great Hammer.
Honestly, I wouldn’t suggest going too much out of your way to get this weapon early in the game, since the Demon’s Great Hammer requires 46 strength to wield effectively, so you would have to pump every available point into strength for many levels just to able to wield it properly. You’re also giving up a more valuable gift in order to get the Black Firebombs as well.
Alternatively, you can wait and get the Demon’s Great Hammer later in the game when you have better stats. Once you run into the character named Snuggly that will trade items, you can trade them a Sack to receive the Demon’s Great Hammer.