Neverborn

Slain during the Primordial war, they fell through the fabric of Creation and left Shadowlands in their wake. As they conceived of a state of 'not being', Oblivion was born. Similarly, their unconscious thoughts created the Underworld, now more static and unchanging to fit their ideals. Like all ghosts, the Neverborn have fetters to Creation and were unable to truly fall into Oblivion. In fact, as they created the world, they have the strongest fetters of all undead. They realized that the only way to achieve their goal of true death was to destroy their fetters, all of Creation. At first, they were more fearful of the Exalted than anything and half-asleep besides the fact. When the Black Nadir Concordat intruded into their tomb-cities and stole the secrets of Necromancy, they were roused to wakefulness and incredibly angry. Though dead, the Neverborn are still incredibly powerful and command hosts of Abyssal Exalts, Deathlords, Hekatonkhires, and Spectres.
Remember Tolkien's description of Sauron's fate at the end of Lord of the Rings? That's the Neverborn. The tragedy isn't that they're "dead", because beings that huge can't actually die - the very concept of Death is beyond them since they didn't build Creation to handle them dying. The tragedy is that they're so obsessed with something they've already lost that they can't look past it. They're all caught in a permanent, inescapable angst-loop, and if any of them could just sit up and notice they could abandon their forms and go back to the Wyld. But instead, they sit and spiral further into their "we got our asses handed to us and now our favorite toy is gone" drain-circling, and the psychic emanation of their collective regret has created an entire Underworld for similarly-resonant souls to live out their own miserable pathos.
Unlike the Yozi, and unlike the truly Dead, the Neverborn are simply incapable of noticing anything that might free them from their eternity of navel-gazing. They have nothing left but self-hatred, and the desire to see everything else wind up even more screwed than they were.
No wonder the Ebon Dragon likes them so much (though not enought to let them win, because everything ceasing to exist would put a damper on his plans for an eternity of subjective and objective hell to everything in existence).