Actually I went back through the last two pages and checked out the three other statted powerhouses, and concluded that Rrahask Sshasaar was now a pushover for the likes of Vildaxaranthus, Conquers Twice, and Alsixnivius. Vil alone, with only 1 or 2 melee attacks per round, without even employing his Power Attack feat (which could add some 30 or 40 extra damage per hit, easy, and still hit Rrahask's AC), deal out 50-90 some damage per round, killing Rrahask in 1 or 2 rounds of focusing on her. If Rrahask cast Heal each round instead of attacking, except for perhaps a Quickened Flame Strike, she'd last maybe 10 rounds or so if lucky (that is, if she had prepared 4-8 Heals), and would only have a mild effect on Vildaxaranthus (along with all those Heals to keep herself in the fight, she could only prepare maybe half a dozen or fewer Quickened Flamestrikes, dealing maybe ~180 damage, and then only because half of Flamestrike is holy damage rather than fire). Even Shapechange likely wouldn't get her a form with high enough AC to avoid getting hit by Vil, and it only takes 2-3 hits for Vil to slay Rrahask.
So for now I've given Rrahask Sshasaar (in the existing post above) a few added defenses from Perfect Timeless Body. Damage Reduction 15/magic and cold iron, Fast Healing 2, and her Reverant Aura (which, while useless against anyone close to her level, at least suppresses fear effects). I'll probably take away/diminish one of these based on further comments, and that'll leave Rrahask in her final form. I'll also consider slowing her resurrection effect from PTB, though as it stands, if anything killed her it's likely that she'd have already wasted several spells against it, and would resurrect with only a partial spell slot inventory ready anyway. Can only waste so many mid- to high-level slots on Tree Stride, Wind Walk, and such, right?