The Demon Knight.

Demon Knights are the spawn of mortals and fiends. While most people who have traces of demonic blood within their lineages ignore or remain blissfully ignorant of them, a demon knight embraces her heritage. The latent unholy energies of the arcane flows through her veins, and the demon knight harnesses and embraces the raw power. They are living fonts of arcane energy, who are gradually transformed by their clumsy attempts to harness and control their demonic blood, into the very creatures from whom they have descended.

Hit Die: D8

Alignment: Any (though most often evil)

Class Skills: Bluff, Climb, Craft, Handle Animal, Intimidate, Jump, Knowledge (Arcane), Ride, Spot, Swim

Skill Points: 2 + Intelligence modifier (x4 at 1^st level)

Demon Knight Class Features

All of the following are class features of the demon knight class.

Weapon and Armor Proficiencies

A demon knight is proficient in all simple and martial weapons and with medium and light armor, and shields (except the tower shield)

Arcane Blast (Su)

A demon knight can directly channel arcane energy in its most primal form. This arcane energy is one and the same with that harnessed by sorcerers and other arcane casters to create spells, but unlike true spell-casters a demon knight cannot shape and control the power of the arcane; she can only channel it into a blast of energy. An arcane blast can be used in place of any normal ranged attack. However unlike a ranged attack an arcane blast is subject to spell resistance (caster level equal to the demon knight’s class level). The arcane blast is used as a normal ranged attack with a range increment of 30’. A demon knight also adds his charisma bonus to the damage of each arcane blast fired.

A demon knight can fire an arcane blast from each hand if she chooses to split her blast. Should a demon knight choose to split her arcane blast, she can fire one from each hand, though the damage for both blasts are divided in half and rounded down (including bonus damage for high charisma scores). Thus at level five a Demon knight can fire a blast from each hand that will inflict 1d6 damage a piece. Normal penalties for two-weapon-fighting apply to attacks with arcane blasts, and they are treated as light weapons for purposes of two-weapon-fighting. 

Arcane Sword (Su)

A demon knight can channel a sustained font of arcane energy, and either her natural attacks or her melee attacks become wreathed in arcane energy that closely resembles unholy flames. The arcane sword ability adds bonus damage as indicated by the class table to melee and natural attacks made by the demon knight. A demon can split her arcane sword ability between two weapons should she so choose. Just as with her arcane blast ability, a demon knight must divide the damage dice for each weapon in half and round down. Thus she must be level nine before her arcane sword ability can be applied to two separate weapons. 

Spell-Like Abilities (Sa)

Starting at 1st level, a demon knight with an Intelligence or Wisdom score of 8 or better gains spell-like abilities. The exact abilities gained depend on the demon knight’s character level, according to the following table. Save DCs, where applicable, are Charisma-based (10 + spell level + the demon knight’s charisma modifier). 

Natural Armor Improvements (Ex)

At 5th level, the demon knight's natural armor bonus increases by +1. A character that does not normally have a natural armor bonus (such as a human) is considered to have an initial natural armor bonus of +0 for the purpose of this ability. Thus, a human's natural armor bonus would increase to +1 at 5th level.

Darkvision (Ex)

At 5th level, the demon knight gains darkvision to a 60-foot range.

Claws (Ex)

At 5th level, the demon knight gains two claw attacks if she didn't already have them. For the base damage of her claw attacks, use the appropriate value from the table below if the base creature did not previously have claw attacks. If she did, use either the value from the table or the base creature's claw damage, whichever is better. The demon knight's claws are natural attacks

Ability Score Changes (Ex)

The indicated ability score increases by the amount noted.

Bite (Ex)

At 10th level, the demon knight gains a bite attack if she didn't already have one. For the base damage of the demon knight's bite attack, use the appropriate value from the table below if the base creature did not previously have a bite attack. If she did, use either the value from the table or the base creature's bite damage, whichever is better. The demon knight's bite is a natural attack. 

Poison Immunity (Ex)

At 10th level, a demon knight becomes immune to all poisons.

Resistances (Ex)

At 10th level, a demon knight gains resistance 5 to acid, cold, electricity, and fire. At 15th level, each of these resistances increases to 10. 
 

Spell Resistance (Su)

At 15th level, a demon knight gains spell resistance equal to her character level (maximum 25). At 20th level, her spell resistance increases by +10 (maximum 35).

Damage Reduction (Su)

A 15^th level or higher demon knight has damage reduction 5/magic. At 20^th level, her damage reduction increases to 10/magic. A demon knight treats her natural weapons as magic weapons for the purpose of bypassing the damage reduction of other creatures.

Wings (Ex)

At 20^th level, a demon knight grows bat-like wings, which she may use to fly at up to her base land speed with average maneuverability. A demon knight cannot fly if she is wearing medium or heavy armor, or carrying more than a light load.  

Demonic Apothesis (Ex) 

At 20th level, the demon knight completes her metamorphosis. Her type changes to outsider (native), and she gains the evil subtype. If the demon knight wasn’t evil before reaching her apotheosis, there is no turning back now; her alignment irrevocably changes to evil. She becomes vulnerable to spells and effects that work on creatures of the outsider type or the evil sub-type, but is immune to effects that target her original type. For example, an evil half-human/half-fiend would be subject to the extra damage from an evil outsider bane sword, but she is immune to hold person because that spell affects only humanoids.