This is indeed interesting, pathfinder on
epic levels:
Hit dice, base attack bonuses, and saving throws continue to increase at the same rate beyond 20th level, as appropriate for the class in question.
So no epic attack/save bonus, so you will end up with characters who laugh at one save and literally cannot make another... also no need to burn feats for higher spell levels (although with epic magic in 3.x who needed those anyway), you simply gain a new level of spells and spell slots every odd level. At even levels they get an additional number of spell levels per day equal to their highest available spell slot...
Well... this is handy for those adventurers who forget their bottomless bags, the [urlhttp://www.d20pfsrd.com/classes/prestige-classes/balanced-scale-of-abadar]balanced scales of some random area[/url] can turn any bag into a bag of holding for hr/class level. Also gives a dandy +2 bonus on those cha checks with outsiders. Of course the prestige class is a divine caster and it references the
planar binding spells which are
arcane... but hey thats just like the
thaumaturgist has the winning flavor of an arcane caster but is a divine only option RAW.
The
diabolist prestige class is literally damned, unfortunate if you die, but o so flavorful
The extra bonus to cha checks when dealing with devils is very nice, especially being untyped
... and another flavorful ability, once a day teleport around hell. Such a great pit stop in the middle of adventuring.
Some of the
spellblights are rather intruiging, like ebon eyes. Invert everything about light. Or the negated property, which gives your SR that can never be lowered... but you have to pierce it to cast