Recall your Guild, Saviors.

The Fairy Soul Gaia is here in Guild Raid!

She regularly uses the "Obliterate" skill regardless of the amount of Mana she has. 

The more Mana she has, the more powerful her skills and damage will be, so you must be careful not to let her Mana pile up.

Here's a Tip from Mephi: 

Try enduring her "Karma Shackles" skill and her mana will reduce! 

And her Physical Resistance is deceased while she's burning so make sure to make use of that chance!