Well for starters, one of the most important things to understand about this fight is that all three princes share the same health pool - so when it's gone, all three of them are done for. However, only one of the princes will actually be vulnerable to DPS at any given time, so it's paramount for your raid's DPS to pay attention to which prince can be hurt at any given time and to switch their attacks and pets to him. Tanks as well - when the health pool switches from prince to prince, it's likely that the tank might not have enough threat on the new target to hold it so everyone really needs to pay attention to threat levels during this encounter. This fight, like many of the boss fights in Icecrown Citadel, is very movement heavy so you'll be shifting positions a lot during the course of the battle.
There's very little difference in this fight in 10/25 man, except you'll be a lot more pressed for space in the 25 man and you'll need more tanks. Since spacing is probably the most important issue in this encounter overall, prepare your raid accordingly.
Each prince will be doing different things during the whole fight, and a "big move" when they "go active" during the course of the fight, as the health pool passes to each one of them. How to you beat them? Read on.

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