It's a "common" item since it is found at numerous places. It's most often found by killing minotaurs such as
Minotaur Lords in the second level of the maze.
Warlord Xuta has a chance to drop it, but given he's an unique enemy with several drop items, odds are against you from getting that exact drop from him. Same goes for the
Orc King, except the orc king respawns giving you multiple attempts.
FYI, reloading a quick save to refight a monster to reroll a drop table is not an effective way to get high tier drops. Not only is that considered an exploit (and thus a prohibited topic onto he forum), the game's code is designed to prevent that type of abuse.