Mauhúr was an Orc in the service of Saruman (he may have been an Uruk, but this is not stated for sure). Mauhúr was sent to reinforce Uglúk's troop as they returned to Isengard with Merry and Pippin. He found them surrounded by Éomer's Rohirrim at the edge of Fangorn Forest, from which he led his Orcs in an attack. This attack was a failure: the Rohirrim were able to defeat the Orcs, even with Mauhúr's reinforcements. Though Mauhúr's own fate isn't known with certainty, it seems that he fell with his soldiers at the hands of the Rohirrim.