Arcane and Divine spell multipliers, progression, XP

I’ve been banging through a custom druid, and I’m starting to feel the itch for a third power source - I’ve always been a fan of Nature/Gaia/whathaveyou as part of a trinity with the extraplanar divine, and the more ‘scientific/physics of magic’ arcane.

So, I’m looking at the various multipliers in the spell types, and seeing where to fit things. More blast, less death/undead, more animal/plant in enchant, less heal, etc.

My main question is thus - is there any math hidden behind the page in how the divine/arcane spell progression, and various spell value multipliers for the categories contribute to the final arcane/divine values, XP and point-wise, when building classes with those multipliers?


That sounds like a fun project. I hope you'll share it with the community when you've got it worked out!

To answer your question, there is no theoretical math hidden behind the page. The spell value multipliers were worked out empirically by looking at the spell levels of various spells in ACKS and finding a way to make them fit. Put another way, the spell creation rules were designed to *model*, not underlie, the existing world of BX/D20/ACKS spells. It was reverse engineering of values established by legacy and tradition.

So for your druid class, look at the long history of druids in various games and you can probably do the same.