Needs review
Source: Encyclopedia Arcane: Conjuration

Description: You have forsaken the ability to call on entities from the upper planes, concentrating instead on creatures from the infernal and abyssal realms.

Prerequisites: Any non-good alignment

You cannot summon or call celestial creatures or outsiders with good alignments through the use of your own spells or magical item effects that do so through spell completion or spell trigger. By giving up this type of conjuration, all fiendish creatures and evil-aligned outsiders you call or summon through the use of your own spells appear with full hit points for their Hit Dice, stay one round longer than their duration would normally permit, and gain a +1 morale bonus to attack rolls and saving throws.