Estir the Spiteful (Heroic)

Strategy

 * Spawned by slaying the groups of, , , and
 * Avoid yellow circles on the floor. If a bat catches you in a circle, it will fly you to the roof and drop you fatally to the floor.
 * During the fight, groups of and  will add.
 * has a buff that increases every 25% from 1 to 4. She can only be damaged when the number of adds alive equals the number of this buff. Use Singular Focus and avoid unnecessarily killing the adds.