MTOF does some great stuff explaining the culture, psychology, and motivations of various races. Particularly impressive: devils as tyrants versus demons as egotists. I love the bit about how devils feel like they don't get the credit they deserve for holding back the demons and preventing the entire multiverse from collapsing into chaos.
I think this would make a solid angle for a Lawful Neutral / Lawful Evil infernal pact warlock PC . . . maybe a self-righteous bastard a la Jack Nicholson in "A Few Good Men." He sees himself as the Man on the Wall, keeping chaos at bay, and he doesn't particularly care if you think he's a bad guy.
I think this would make a solid angle for a Lawful Neutral / Lawful Evil infernal pact warlock PC . . . maybe a self-righteous bastard a la Jack Nicholson in "A Few Good Men." He sees himself as the Man on the Wall, keeping chaos at bay, and he doesn't particularly care if you think he's a bad guy.