Problem with 1 F is that it ' s a 10 m cast range though so if you ' re in a boss fight it will aggro you before your guys can set up aggro before your 4 hits with the 2 . 5 s cast . You could have them go in first and then move into 10 m range , but it ' s better to stay out of 10 m range in the beginning to ensure nothing can stop you from your imprison rotation . Moving into 10 m cast range also prevents you from stacking attack damage buff from Thrall unless you decide to drop thrall after you move into 10 m cast range but then that delays your soulburn for party so it ' s just overall better to start casting from 15 m , having thrall around 1718 m so you sit in the AoE while casting . Ideally with a 4 man party and you ' re playing Warlock you want people to go in while 4 is being casted so that you don ' t draw aggro for hitting it first with a 35 k crit and leaving 1 F for when leech casting is on CD