Unique. Troll. 1 strike. Also playable at Moria and The Under-gates. If Doors of Night is in play, playable at any Under-deeps site. Any non-unique Orc or Troll hazard creature can be played (not counting against the hazard limit) on a company that has faced Umagaur that turn.
"Then came Umagaur the Warlord, 'Werewolf-slayer,' self proclaimed 'Troll-king of the Hithaeglir.' And in his wrath he slew most of the Dwarf-company."
-Kuduk Lore