Half-fiends are creatures heavily tainted with demonic, infernal, or other evil power.
“Half-fiend” is an inherited or acquired template that can be added to a living, corporeal creature with an Int score of 4 or more. A half-fiend uses all the base creature's statistics and special abilities except as noted here.
CR: HD 4 or less, as base creature +1; HD 5 to 10, as base creature +2; HD 11 or more, as base creature +3.
Alignment: Any evil.
Armor Class: Natural armor bonus improves by +1.
Defenses/Qualities: Gains darkvision 60 feet; immunity to poison; acid, cold, electricity, and fire resistance 10; DR 5/magic (if HD 11 or less) or 10/magic (if HD 12 or more); and SR equal to creature's CR + 11 (maximum 35).
Speed: Unless the base creature flies better, the half-fiend flies at twice the base creature's land speed (good).
Melee: A half-fiend gains two claw attacks and a bite attack. Damage depends on its size.
Special Attacks: A half-fiend gains the following.
Once per day, as a swift action, the half-fiend can smite good as the smite evil ability of a paladin of the same level as the half-fiend’s Hit Dice, except affecting a good target. The smite persists until target is dead or the half-fiend rests.
Spell-Like Abilities: A half-fiend with an Int or Wis score of 8 or higher has a cumulative number of spell-like abilities set by its HD. Unless otherwise noted, an ability is usable 1/day. CL equals the creature's HD (or the CL of the base creature's spell-like abilities, whichever is higher).
Abilities: A half-fiend gains a +4 bonus on three ability scores of its choice and a +2 bonus on the other three.
Skills: A half-fiend with racial HD has skill points per racial HD equal to 6 + Int mod. Racial class skills are unchanged, and class level skill ranks are unaffected.