In Baldur's Gate 3, searching for the vicious beast master is part of the mission to avenge the drowned man. The vicious beast master is the Red Hammer. Under the stairs of the port pier, there is an NPC to talk to. The one squatting there is, After arriving at Flem's cargo, a battle will be triggered, and you can use him to get to the Iron Throne first.
1. The vicious beast master is the dwarf Red Hammer of the submarine. This branch can be completed together with the Iron Throne mission.
2. First come to Flem Cargo , then a battle will be triggered, and then you will deal with four vicious beasts.
3. You will then be prompted that there is an abnormality in the house. Go into every house on the pier and look for the basement to find it.
4. Don’t worry about the Red Hammer on the submarine for now. Use him to get to the Iron Throne first, and then deal with him to avenge the Drowned Man.