Just to make things clear...
The sword that Bloodsailor mentioned is something totally different from "The Halberd of Rock". That halberd drains your stamina even when it's in your inventory. So, sell that halberd for some nice cash as soon as possible.
Keep the sword (However you can't wield it yet), you will come across a dagger and an amulet with same descriptions on them as the sword has.
I can't give more info or it will be a big spoiler. If you want spoilers about this items, just search the forum.
