In Pathfinder Campaign Setting: Lords of Chaos, James Jacobs describes the Abyss, its demon lords, and special powers mortal characters can gain if they worship these evil beings. These latter are called boons, the weakest of which are spell-like abilities, though those powerful mortals who delve deep into this evil gain even stranger powers. Access to the boons requires taking the Demonic Obedience feat.
You physically defile yourself, others, or holy objects in order to prove your blasphemous devotion to a demon lord and gain special boons. Prerequisites: 3 ranks in Knowledge (planes), must worship a demon lord. Benefit: Each demon lord requires a different obedience, but all obediences take only an hour to perform. Once the obedience has been performed, you gain the benefit of a resistance to some element or attack associated with your demon lord, as indicated in the "Obedience" entry for the demon lord.
If you have at least 12 Hit Dice, you also gain the first boon granted by your demon lord upon undertaking your obedience. If you have at least 16 Hit Dice, you also gain the demon lord's second boon. If you have 20 Hit Dice or more, you also gain the demon lord's third and final boon. Unless a specific duration is listed, a boon's effects are constant.
If you ever fail to perform a daily obedience, you lose all access to resistances and boons granted by this feat until you next perform the obedience.
Here are just a couple of boons from the more than 30 demon lords presented in the book.
Abraxus: 1st boon: Secret Lore (Sp)identify 3/day, augury 2/day, or illusory script 1/day 2nd boon: Heretical Revelation (Su) Up to three times per day, you can whisper terrible secrets to an adjacent target as a standard action. The target can resist with a Will save (DC = 10 + 1/2 your HD + your Charisma modifier). If the target fails its save, it is stunned for 1 round, then confused for 1d4 rounds, and then nauseated for 2d6 rounds. This is a mind-affecting effect. 3rd boon: Penultimate Incantation (Sp) Up to three times per day, you can affect a single creature within 60 feet with a targeted greater dispel magic. Each spell or effect dispelled inflicts fire damage to the target equal to the result of your caster level check made to dispel that effect.
Pazuzu: 1st boon: Whispers on the Wind (Sp)charm person 3/day, enthrall 2/day, or fly 1/day 2nd boon: Possession (Sp) You can cast magic jar once per day as a spell-like ability. You can use a holy symbol of Pazuzu or a statue of Pazuzu as your receptacle—if you do so, you can determine the exact creature type and position of all potential life forces you're capable of possessing. 3rd boon: True Temptation (Sp) If any creature speaks Pazuzu's name aloud three times with a single breath, and that creature is within 60 feet of you, you can cast quickened charm monster on that creature as an immediate action. You can use this power up to three times per day. Creatures with fly speeds take a –4 penalty on saves against this effect. If a creature that fails its save against this effect has protection from evil or a similar effect activated, that effect is immediately and automatically dispelled.
As for what the actual obediences are, you'll have to just wait and see....