D&Dtools1

With careful exploration, a spellcaster who feels a call from within can slowly bring the power of their fiendish lineage to the surface.

Requirements

Class Features

Spellcasting: At each new fiend-blooded level except for 10th, you gain new spells per day and an increase in caster level (and spells known, if applicable) as if you had gained a level in a spellcasting class to which you belonged before adopting the prestige class. You do not gain any other class benefit a member of that class would normally gain, except that your fiend-blooded levels also stack with any other arcane spellcaster levels for the purpose of determining familiar abilities. If you had more than one spellcasting class before becoming a fiend-blooded, you must decide to which class to add each level for the purpose of determining spells per day, caster level, and spells known.

Fiendish Companion: Your familiar benefits from your fiendish heritage. The fiendish template (described on page 108 of the Monster Manual) can be applied to your familiar, if you so desire. Since this is not possession but rather a sympathetic link, the familiar's alignment need not shift to evil.

Fiendish Heritage (Ex): You draw strength from your fiendish ancestor's essence as you gain increased mastery over your lineage.

At 1st level, a subtle toughening of your physical form grants you a +1 natural armor bonus to AC.

At 3rd level, you gain a +1 boost to your Charisma score.

At 5th level, you gain a +1 boost to your Intelligence score.

At 7th level, you gain a +1 boost to your Dexterity score.

At 9th level, you gain a +1 boost to your Constitution score.

Fiendish Sorcery: You gain insight into the power of your fiendish heritage, and this insight strengthens your spellcasting prowess. At 2nd level, and again at 4th, 6th, 8th, and 10th level, add one additional spell to your spells known list. Each new spell must be of a level that you can cast but can be any spell having the fire descriptor or any spell from the schools of enchantment, illusion, or necromancy. Thus, you could add fireball (a fire spell) or speak with dead (a necromancy spell) to your 3rd-level spells known (even though you are an arcane caster and speak with dead is normally a divine spell), but not lightning bolt (which neither carries the fire descriptor nor belongs to one of the three specified schools).

Blood of Fiends (Ex): Upon reaching 3rd level, you gain a +1 bonus on saves against poison. You also reduce any damage taken from poison (whether hit point or ability damage) by 1 point.

Starting at 6th level, your fiendish essence grants you resistance to cold and fire 5.

Upon reaching 9th level, you have unlocked much of the power of your fiendish lineage, gaining resistance to acid and electricity 5.

Smiting Spell (Su): If you are a fiend-blooded of at least 4th level, you can as a free action, once per day, invest a portion of your fiendish power into any damaging spell you cast. The resulting spell will deal an additional number of hit points of damage equal to your fiend-blooded class level + Charisma modifier to all within the spell's area.

Starting at 8th level, you can use smiting spell twice per day.

Fiendish Exaltation (Ex): At 10th level, you unlock the final secrets buried within your lineage. In addition to the ability boosts you gained from your fiendish heritage, you now gain an additional +1 to Dexterity, Constitution, and Intelligence, and +2 to Strength. You also gain complete immunity to poison, and damage reduction 10/magic.

Advancement