Ethereal DefilerHD: d8
Level BAB Fort Ref Will Features 1 +1 +0 +0 +2 Tainted Body, Tainted Energy
2 +2 +0 +0 +3 Ethereal Scales, Str +1, Cha +1
3 +3 +1 +1 +3 Tainted Arts, Str +1
4 +4 +1 +1 +4 Defensive Insight, Defiled Sight, Cha +1
5 +5 +1 +1 +4 Ethereal Bore (full-round), Str +1
6 +6 +2 +2 +5 Growth, Cha +1
7 +7 +2 +2 +5 Swift Strike, Str +1
8 +8 +2 +2 +6 Ethereal Bore (standard), Cha +1
9 +9 +3 +3 +6 Anchoring Aura, Str +1
10 +10 +3 +3 +7 Ghost Stalker, Cha +1
11 +11 +3 +3 +7 Piercing Taint, Str +1
12 +12 +4 +4 +8 Ethereal Bore (move), Cha +1
13 +13 +4 +4 +8 Endless Bore, Str +1
14 +14 +4 +4 +9 Hideous Taint, Cha +1
15 +15 +5 +5 +9 Roiling Energy, Str +1
16 +16 +5 +5 +10 Ethereal Bore (free), Cha +1
Skills: 4+int mod. Class skills are Climb, Hide, Jump, Listen, Move Silently, Spellcraft, Spot, Survival.
Proficiencies: Ethereal defilers gain proficiency with their own natural weapons.
Features: Tainted Body (Ex): At 1st level, the ethereal defiler loses all other racial bonus and gains aberration traits (darkvision 60 feet, basically). It’s a medium sized aberration with base speed 40, two natural claw attacks (1d6+Str) and a natural tail attack (1d6+half Str). The claws are considered to be its primary natural attack, while the tail is secondary.
The ethereal defiler gains a natural armor bonus equal to its Str or Cha modifier, whichever is higher.
Tainted Energy (Sp): At 1st level, the ethereal defiler has the ability to unleash a blast of eldritch energy from its body as a standard action. This blast is a ranged touch attack with a range of 10 feet per HD that deals 1d6 magic damage per HD.
Alternatively, the ethereal defiler can imbue one of its claw attacks with this energy as a swift action, dealing the same damage plus the damage of the claw. This energy dissipates at the defiler's turn if not used.
Any creature damaged by this energy must make a Fort save or be sickened for 1d4 rounds (DC 10 + half HD + Cha mod).
Ethereal Scales: At 2nd level the ethereal defiler gains fast healing and DR/cold iron both equal to half its HD. It also receives the Extraplanar subtype, with its plane of origin as the Ethereal Plane.
Tainted Arts: Ethereal defilers, despite their capable magic, revel in tearing foes apart with their claws and can develop several powers to assist with this. At 2nd level and every 2 other levels thereafter, pick one of the following options. Unless otherwise noted, each ability is permanently active, and they're all supernatural abilities.
Twisted Elements: As a free action, change the type of damage your Tainted Energy deals to any of fire, acid, cold, or electricity. You cannot change it again for 1d4 rounds.
Twisted Insight: Upon choosing this ability you permanently add your Cha modifier to all saving throws you make.
Twisted Sight: You must have at least 4 HD to choose this ability. You gain the ability to see perfectly in darkness, even magical darkness, out to a range of 30 feet. Also, you can see invisible creatures within the same distance.
Defiler's Word: You must have at least 4 HD to choose this ability. You may, every 1d4 rounds, target an object or area as the Shatter spell. If someone is wearing or holding the target when it is shattered, they must make a Fort save (DC 10 + half HD + Cha mo) or be dazed for 1 round and deafened for 1 minute.
Lesser Bore: You must have at least 6 HD to choose this ability. You may, every 1d4 rounds, use Dimension Door as a spell-like ability, except it is limited to short range and you may activate it as a swift action.
Wings of Taint: You must have at least 6 HD to choose this ability. You gain a fly speed equal to your base land speed with good maneuverability.
Claws of Hate: You must have at least 8 HD to choose this ability. You may take a full-round action to imbue your claws with an enhancement bonus to attack and damage rolls equal to half your HD. You may (and must, after 10 HD) "spend" points of this bonus to gain properties such as Keen or Bane instead, with the exception of abilities that have a limited number of uses per day. This bonus lasts for a number of rounds equal to your HD.
Defensive Insight: At 4th level the ethereal defiler gains SR equal to 11 plus its HD, plus resistance to fire and cold equal to its HD. It may raise or lower its SR as a free action at any time even if it isn't its turn.
Defiled Sight: At 4th level, the ethereal defiler gains blindsense with a range of 5 feet per HD and telepathy with twice that range. Also, the ethereal defiler may see into the Ethereal Plane from the Material Plane and vice versa at all times.
Ethereal Bore (Su): Starting at 5th level, once per day per HD the ethereal defiler may shift to the Ethereal Plane as the spell ethereal jaunt, except it requires a full-round action that does not provoke attacks of opportunity. The defiler may remain on the Ethereal Plane as long as it wishes. It may return to the Material Plane at any time as another full-round action, dealing 1d6 points of damage per HD in a 20-foot radius centered on itself. Once it has returned to the Material Plane, it cannot reenter the Ethereal Plane for 2d6 rounds.
At 8th level, it may use this as a standard action.
At 12th level, it may use this as a move action.
At 16th level, it may use this as a free action.
Growth: At 6th level the ethereal defiler increases in size. It becomes Large; recalculate all natural weapon damage appropriately.
Swift Strike: At 7th level the ethereal defiler’s tainted energy ability can be applied to its natural weaponry as a free action, allowing it to make multiple attacks imbued with its energy damage.
Anchoring Aura (Su): At 9th level, an ethereal defiler projects a 20 foot aura that inhibits spells with the teleportation descriptor. Furthermore, all creatures within the aura must succeed on a Will save (DC 10 + half HD + Cha mod) to move more than 20 feet from the creature.
Ghost Stalker (Su): At 10th level, the ethereal defiler gains the ability to drag foes to the Ethereal Plane. It makes a grapple check; provided it succeeds in holding the target, it may shift to the Ethereal Plane as a swift action, bringing the target with it. Once there, it can end the grapple with no ill effects.
Piercing Taint: At 11th level, the ethereal defiler's Tainted Energy blasts are treated as non-magical: they pierce spell resistance and magic immunity and are not suppressed by antimagic field and the like.
Endless Bore: At 13th level, the ethereal defiler may use its Ethereal Bore ability at will instead of once per day per HD.
Hideous Taint: At 14th level, any creature that fails the fortitude save against the defiler's Tainted Energy is nauseated instead of sickened.
Roiling Energy: At 15th level, the ethereal defiler’s tainted energy blast becomes unstable enough that it may make iterative attacks with it.
I'm missing an 11th and 14th level ability. Starts with 3 natural weapons and a scaling ranged attack. Has warlock casting, with much higher eldritch blast damage, but it's 2 levels behind other warlocks for invocations. Gains its signature ability at level 5, which continues to improve as it levels up. Anchoring Aura comes online about the same time Teleport does. More skill points than normal because it's supposed to be a cunning predator; same with the extra skills. Swift Strike is basically Edritch Glaive with no reach in exchange for working with natural attacks which, at Large size, will already have reach. Designed as a melee class with decent ranged support. Use Ethereal Bore to get in close then spam Tainted Energy claws everywhere.