Karsil was a greatsword of alarming size and was wielded by Bane IV, replacing the mace that he wielded and destroyed during the Battle of the Misty Mountains. It was his primary weapon throughout the rest of the Mortality Crusade.
Karsil was a greatsword of nearly two metres, and was styled like Orcrist. It was made of Mithril, and was thus completely indestructible after it was forged. Upon the flat of its blade were the inscripted words 'For Durin. For Moria. For my people!' in Elvish. These were the famous last words Threnn Stonefist, in whose name the sword was forged. The hilt was jewelled at the hilt by a bright red gem and its hilt was wrapped in the skin of a Warg.