The level 100 to 110- dungeon has 8 bosses but you will only encounter 3 per run. Violet Hold is a prison and it is coincidence which bosses will come out to fight. The possible bosses are:
- Mindflayer Kaahrj
- Millifiecent Manastorm
- Blood-Princess Thal’ena (daughter of Lana’thel in ICC)
- Fel Lord Betrug
The 68 rare items of loot in this dungeon require level 100 and have an itemlevel of 820 on level 110.
For more information see wow-head.