Demons. The creatures you love to hate (or who love to hate your character!). You can get an Abyssal-sized serving of these creatures, their organizations, their powers, their tactics, and more in Fiendish Codex I: Hordes of the Abyss. Make no mistake, though. This book has a lot of crunchy bits for the players of characters who have it in for demons, too! Take a look at some of the excerpts we're providing for your fiendish amusement. The excerpts below include information about nabassu, Yeenoghu, three feats, and the location known as Pazunia.
Poison isn't always bad for you.
Prerequisite: Great Fortitude, Con 13.
Benefit: Any time you succeed on a Fortitude save against a poison, you heal a number of hit points of damage equal to your Constitution bonus.
THRALL TO DEMON [VILE]
You formally become a supplicant to a demon lord. In return for your obedience, you gain a small measure of that demon lord's power.
Prerequisite: Chaotic evil alignment.
Benefit: Once per day, while performing an evil act, you can call upon your demonic patron and gain a +1 luck bonus on any one attack roll, saving throw, ability check, skill check, or level check.
Special: You can take this feat only once. If you take it, you cannot take the Disciple of Darkness or Scion of Sorrow feats (both described in Champions of Ruin), which link you in a similar way to powerful archdevils or yugoloth lords.
VESTIGIAL WINGS [ABYSSAL HERITOR]
A pair of vestigial wings sprouts from your shoulders. Benefit: Your wings aren't formed enough to allow true flight, but they do enhance your ability to jump. You gain a bonus on Jump checks equal to +3 per Abyssal heritor feat you possess.
Your wings can also slow your fall. As long as you can take move actions, you can control a fall so that you land without taking damage. You cannot, however, alter the direction you fall.
Special: Because your wings create additional drag while you swim, you take a -2 penalty on Swim checks.