Horn of Shattering is a quest in the PC version of Crusaders of Might and Magic. Celestia wants to use the Horn of Shattering to break into Stronghold and fight Necros. She asks Drake to fetch the horn from the dwarves of Corantha.
After reaching the other side, he'll come to Duskwood, where the dashers and ogres will attack him on sight. He then reaches Corantha, where the dwarven leaders tell him that King Stoneheart has been killed, and his son Dain has been kidnapped by the Ironpick rebels. Drake must travel to the Corantha Mines and free him from their grasp (completing the Rescue the Dwarven Prince quest).
When Dain is back in the throne room, he tells Drake that he wants to give him the Horn of Shattering, but doesn't have the authority to do it without the Scepter of Regency - the symbol of rulership among the dwarves. Drake must travel back to Duskwood and retrieve the scepter from a group of ogres (completing the Recover the Scepter of Regency quest).
When Drake gives the scepter to Dain, he receives the Horn of Shattering, and can finally deliver the artifact to Celestia.