Indeed, making deals with devils would be somewhat unwise for a good leaning neutral PC!
As for looking into your PCs bloodline, various methods exist, there are some cleric spells iirc that can be used there, Peraga could develop a ritual or talk to PCs who have done something along these lines or she could come up with some magical ritual herself. I don't know at the top of my head if anything exists in the source material, but we are rather flexible with these things, so provided it makes some sense we are rather flexible in what we accept there. Magic is to a degree rather flexible in the realms. I don't mind helping out there if you want.
That being said, with some general pointers, there are a few ways you could approach this:
- Knowledge is power. Knowing what sort of being to call into service at any given time can be highly important. This could be represented with summon reskins, given Amia's variety in this aspect there are many ways you can go there depending on what you are interested in. This is just one example mind, there are many others.
- Develop new abilities. Amia has spellwidgets, meaning you can get almost any spell or spell like ability (which includes monster abilities http://nwn.wikia.com/wiki/Category:Monster_abilities ) as a spell for your PC. This obviously has to be in some reason
- Emulating abilities on gear. This one is a bit nebulous and depending on whether Peraga is an unsubraced halfling, may be a little tricky. But we do allow certain traits she might gain to be emulated on gear.
Will do that!