Ulma leads the Gur, a group of monster hunters. Their children have been kidnapped by Cazador's spawn, and they have been camped in Rivington trying to mount a rescue or seek revenge.
Ulma and her fellow Gur can be found in the Gur Camp attending a funeral for the fallen from a recent offence on Cazador's palace. She will ask the party to help in defeating Cazador and discovering the fate of their stolen children.
Once Cazador is defeated, Ulma and the Gur can be found near the waypoint in Cazador's Dungeon. She will thank the party for their assistance and provide her support for the final battle if the ritual was not completed, or attack if it was.
If Astarion had been turned in to Gandrel in the Act One and kidnapped, then in Act Three Ulma and all her fellow Gur will be dead (except Gandrel) . If spoken to via Speak with Dead, she will tell the player that the whole tribe was massacred by Cazador, who assaulted their camp to reclaim Astarion. She will also provide some of the information that could otherwise be acquired through The Pale Elf quest.
Throw all caution in the wind to gain Advantage on your melee Attack roll.
Until your next turn, you have Advantage on all Attack Rolls, but enemies also have Advantage on Attack Rolls against you.