The Guns of Avalon

Synopsis - Amber back towards his magic realm strides Corwin, Prince of Amber, as the dark powers of the shadow worlds rise against him... Recently escaped from the dungeon where he was imprisoned after his brother, Eric, usurped the throne. Corwin, Prince of Amber, is determined to use all his super human powers to regain his stolen birthright. But the road back to Amber was paved with unknown perils and to reach it Corwin must first fight his way through the dreaded forces of the circle of evil, and the weird demons conjured up by his own terrible curse.

Synopsis from Open Library.