All Devilbound get the following adjustments:
CR: same as the base creature +1
Alignment: Any evil. Devilbound creatures have an evil aura as if it were an evil outsider.
Senses: Gains darkvision 60 ft.
Armor Class: Natural armor improves by +4
Defensive Abilities: Gains a +4 bonus on saving throws against poison, resist fire 30, and regeneration 5 (good spells, good weapons)
Weaknesses:
Contract Bound (Ex): The creature has signed a contact of service in return for this template. The devil must reveal its nature as a creature of Hell when it offers a contract, and it can't hide the details of the contract in any way. The creature must enter the agreement willingly (without magical compulsion). Usually the creature must perform one or more tasks for the devil, and in exchange, the creature gains the template's abilities, whether immediately, after a specific amount of time, or once the task has been completed.
Special Attacks: Gains the summon universal monster ability and can summon a devil once per day with a 100% chance of success. The devil remains for 1 hour. The creature's caster level or Hit Dice, whichever is higher, determines the most powerful kind of devil it can summon and the effective spell level of this ability, according to the following table:
Spell-Like Abilities: The creature gains the following spell-like abilities depending on the devil it is bound to. The creature uses its Hit Dice or caster level, whichever is higher, as the caster level for its spell-like abilities. Save DC's are based on the creature's Intelligence, Wisdom, or Charisma, whichever is highest.
Abilities: Adjust the base creature's ability scores according to the kind of devil it is bound to.