The Greathammer has official stats in the Monster Manual IV (pag. 101), is this meant to replace or it is another kind of hammer? Ezzetabi 19:33, May 24, 2010 (UTC)
The Greathammer is an Exotic weapon, not a martial.
1d12, 19-20 x4 are the stats on the hammer and it increases to 3d6 for large characters. It is an exotic weapon (Which means you take a feat for it). I also believe it has no listed price which would mean you must homebrew a price for it or take it from a Greathorn Minotaur, which would mean the DM would have to homebrew a price for it if the PCs wanted to sell it, or deny the PCs because "it wouldn't sell since not many can weild such a large hammer".