Advice for Working with Devils (3.5/PF)

[Talverin]

I am playing a level 15 Arcanist in an Underdark-based game. In this game, we are all working for a Devil that has us contracted in his employ. My Arcanist was born and raised in a cult following a Devil (Whose name the DM has kept hidden from us) and his service has continued into adulthood.

I'm looking for Devil-themed spells, abilities, and similar.

For example:

Hellfire Ray: Scorching ray, but more damaging, and half the damage becomes Unholy, (Basically untyped). When killed by this ability, the target's soul... Goes straight to Hell.

Unholy Metamagic: 50% of a spell's damage becomes Unholy, Good characters are at a -2 Save, Evil gets a +2. I spoke with my DM, and he allowed the Hellfire Ray ability to send their souls to Hell.

I'm looking for things that are thematic, and preferably effective also.

My opposition schools are Enchantment and Illusion (Taken because the other party mage is an Illusion/Enchantment specialist and I didn't want to step on their toes.) so everything else is on the table. I am an Evocation (Admixture) School Specialist Arcanist.

[Malphegor]

Investiture of the (type of devil) spells are fun. I forget what book they're from, but basically you buff your party with interesting abilities that resemble the devils they're based on.

Presumably you're partially summoning a devil to posess them for a bit, so that's entertaining, roleplayingwise.

My favourite one is the bearded devil one. Bam, ranger, now any time something attacks you for a bit your beard (actually the flesh underneath, stretching, but hey if you have a beard anyway) will of its own accord attempt to attack and grapple your foe!

[Buufreak]

Investiture of the (type of devil) spells are fun. I forget what book they're from, but basically you buff your party with interesting abilities that resemble the devils they're based on.

Fiendish Codex 2 is the book all about devils and devil-kind. The aforementioned spells originate there, as well as many character options such as spells, feats, classes... There's also the Faustian Pact rules, but that is edging towards "ask your DM" territory, so tread lightly.