wanted to ask for this class, the Demonologist. It's a Encyclopedia Arcane PrC that you can take as a 2nd level wizard. It's not to terribly broken, since all of the crazy demon summoning stuff I can do with the class features is actually up to you (you get to choose what names I find and can control, after all).
I would also ask if we could use the rituals for other creatures, such as the angels/devas/ect. (nothing is more evil than making an angel destroy a church, after all).
Link to book for casual glancing, and I'm happy to answer any questions you would have about it.