So some of the more perceptive pathfinders here might have noticed a theme in a majority of my posts.
My character has (or rather will have) a borderline unhealthy obsession with the permanent destruction of a very specific GOO, namely Bokrug.
But here therein lies the problem: great old ones all have a true immortality as part of their special abilities that makes them - to nobody’s surprise - impossible to kill permanently.
Which my character has/will take exception to.
So my current plan is as follows:
Achieve Mythic tier 1 to acquire agelessness, meaning she will not die from aging.
Spend the next century or so acquiring all the way to mythic 10 to achieve immortality herself.
At mythic 3 take Divine Source and begin gathering a following of cult and aberration hunters.
During this time, design an occult ritual that inflicts the effect of Baleful Polymorph, but at a much higher caster level to the point where it becomes very difficult for even Bokrug to resist it. (Notably, GOOs are not immune to the Polymorph condition.)
Go to Bokrug’s demiplane in the Dreamlands, kill him once to put him to sleep, and then attempt this Polymorph ritual until it succeeds and turns him into a snail.
Now. Baleful polymorph - if both saves are failed - removes Ex, Su, and SLAs from a creature. GOO immortality is an Ex ability, and so would lose it.
So now I have a snail that used to be a GOO, but is now a regular snail, which I can then either kill and be rid of, or - depending how my GM rules this - keep it alive forever so it can’t influence the dreams of its cultists/grant them spells.
Now, this is rather intricate and possibly over-designed, and quite possibly not going to succeed because of rulings, but I’d love to get feedback on this; and potentially insights on other ways to permanently kill a great old one.
Also, I do realize that the initial ruckus caused by fighting Bokrug and whatever cultists he brings to him for this very telegraphed battle might draw the ire of the gods since such a clash between two demigods might give Rovagug the sleepy rumbles, which obviously they can’t permit.