Atareth's heavenly essence helps against some of the damage, but she still takes a whalloping 56 damage (post-DR).

Telepathy to party: "Everyone move back 5 feet! Please don't forget to give me and Taleira this 5' buffer. I am going to set up some fun for them with a blade barrier ... they can't ignore it, and only two would then be able to come through - after getting hurt - to engage and can't strike across without getting hurt. Taleira, move back and ready a storm when they cross!"

Atareth waits for her sisters to clear. With the fighters having just gone, she knows she'll be able to time it right before the enemy gets a chance to attack again.
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Ready action: Once friendlies back up enough for Taleira and I to move 5' back ourselves, she will move back 5' drop a blade barrier in front of where she was standing.

This way, the space is open so it is not dropped "on" the space of the bad guys are standing, which would allow them a Reflex save for no damage (vice half) to be on the desired side. They don't get that option, but now must decide to cross or to use missile weapons/ spells.