Hey all!
(assuming you are still out there?)
I've been thinking a bit about this adventure myself. However, I think a number of logic gaps appear when you try and convert it to a Level 100 adventure.
In fact none of it actually makes sense from a 100th-level perspective.
Orcus is only CR 56 as I rate him (and much much weaker by the official rules). Which basically puts him down as cannon-fodder for a party of 4-5 100th-level characters. In fact even boosting Orcus to Greater Power, may not be enough.
Basically a 100th-level party are the equivalent of powerful Lesser Gods. So I think you would need an Elder One to challenge them as the final boss.
So you end with a massive philosophical gap, which needs to be addressed first, and then worked backwards.
One other point of note is that with a 100th-level part, I wouldn't go any lower than using CR 66 opposition (maybe as low as CR 50 for some random encounters). Which basically rules out more or less everything in the Epic Level Handbook...at least everything pre-Template that is.
While you can offset this a degree by using multiple opponents at once, you don't want to rely on this all the time.
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