This creature looks like a 6-foot tall humanoid whose form is composed of dark matter. Its head is featureless and sports no eyes, ears, nose, or mouth. It wears no clothes and bands of silver and white crackle and dance in its form.
Speed 30 ft.
Str 19, Dex 16, Con 24, Int 14, Wis 16, Cha 14
Being composed of negative energy, a netherspark radiates an aura of such energy in a 10-foot radius. Any living creature within this area takes 1 point of damage per round until it leaves the area. Undead in the area heal 1 hit point each round they remain in the area. Undead cannot more hit points than their normal total from the netherspark's aura.
Once every 1d4 rounds, a netherspark can release a burst of negative energy in a 20-foot radius around it. Creatures in the area take 1d8+10 points of negative energy damage. Undead take no damage but heal a number of hit points equal to what the ray would otherwise deal.
Once per round as a standard action, a netherspark can release a ray of negative energy with a range of 40 feet as a ranged touch attack. A target hit takes gains one negative level if it fails a DC 22 Fortitude saving throw. On a successful save, the target avoids the negative level but still takes 1d8 points of negative energy damage. The save DC is Constitution-based.