Haha, the hardest? The deathsinger phase is by far the easiest of the 4 phases for CE. 3 left, 3 right, wizards lured out, kill them. All 5 go to right side, start killing Knights with sword outside doorway while 6th takes out 2 shriekers. Once shriekers are dead, the knights on right side should be dead, so begin killing knights, acolytes and thrall inside right doorway. Once she begins Liturgy, she becomes immobile for 30 seconds, plenty of time to kill her with ease. It's stupid how easy she is and no one tries, assuming she's hard or doing stupid things to make her hard. In the end, people waste more time looking for a Crota CP when they could spend 5 minutes tops on Deathsinger phase and be done with it.