So, I was flipping through the FC2 yesterday when it occurred to me that the Investiture spells were actually a pretty good idea, and that it would be worth it to make such spells for things other than Devils. Does anyone else think so? Does anyone have opinions on the balance/brokenness of those spells?
On a related note: Are their any Eladrin other than those found in the MM and the BoED? They don't seem to be in Planes of Chaos.
Investiture spells are probably alright on the balance-level, but with the slight cost of the "price on the soul" (not really reflected in game terms) and the fatigue that follows. Nothing really out there like Corrupt or Sanctified spells.
For other investiture spells, I'd say you need a good link to the forces your investing with, otherwise you shouldn't be casting them.
As for Eladrin they were introduced in D&D rules through the Planescape Monstrous Compendium II. All of them have been converted to 3.5e rules except for the Shiere and Noviere Eladrin. The Shiradi are a new subrace introduced in BoED.