The Wraiths, otherwise known as Elemental Wraiths or the Firstborns, were godlike beings originally from the realm of Argent D'Nur. They were revered and worshiped by the Argenta, who formed the Night Sentinels to protect them. In turn, the Wraiths empowered the Night Sentinels with Sentinel Energy, making them nearly invincible against the demonic forces of Hell.
The Wraiths were the very first lifeforms on Argent D'Nur. According to the Ligra Sultagenta (Book of Kings), an immense shard of rock and metal known as the Cosmic Spear impacted Argent D'Nur, impaling through the planet. The impact opened the "Womb of the World" and released the Wraiths, who then brought life to the planet in what is known as the Wraithcall. Fierce beasts and an unforgiving biosphere rose from the Wraithcall in which the first of those were the Ancestrals, towering behemoths invigorated by the magic of the Wraiths who waged war with each other for years untold and destroying everything in their wake. The Wraithcall soon gave rise to the Argenta and the Wraiths gifted early man with magic and inspired them to drive back the Ancestrals and claim dominion over Argent D'Nur. The Argenta owed gratitude to the Wraiths and worshiped them as their gods, and forming the order of the Night Sentinels to protect the Wraiths and their civilization from outside threats.
During the Time of Grief, the Argenta shifted their worship of the Wraiths to the Maykrs after the divine-like advanced race allied with the Argenta by providing them advanced technology and safety from Argent D'Nur's harsh environment along with promises of eternal peace in Urdak. During the Unholy War against Hell, the Maykrs and the Order of the Deag discovered the potentials of combining the demons' Hell Essence and the Wraiths' powers to create Argent Energy, an extraordinary energy that could end or enhance life.
However, the Argenta soon came to learn about the Maykrs' unholy pact with the Dark Lord of Hell. The non-indoctrinated Argenta rejected their worship of the Maykrs and returned to the way of the Wraiths.
Fall of the Wraiths
A Night Sentinel, Commander Valen, lost his son in the war against Hell and was haunted by demonic visions of the boy's tortured existence. Desperately wanting to free him from his torment, Valen was approached by the Hell Priest Deag Grav with promises of resurrecting his son for a price: the keys to the Sepulcher of Elements and opening the vault of the sleeping Wraiths. Valen relented and Hell's forces abducted the ancient creatures, transporting them to Hell where they all were cursed and subjugated, and were used to fuel the Well. The Argenta fell and the Night Sentinels were scattered across Hell and killed to the last man. As for Valen, who has since been condemned as the Betrayer, he only had his son resurrected in the form of a powerful demon, the Icon of Sin.
For the next three ages, until the fourth age the Wraiths were under Hell's corruption, the Wraiths were strung to sacrificial altars that siphoned their elemental energy into powering the Well, giving demons unlimited Argent Energy to use in their conquests.
The Wraiths were eventually freed by the Doom Slayer; the Slayer traveled to the ruins of Argent D'Nur and by using the Crucible he breaks the Wraiths free from their bondage, and subsequently depriving The Well from Hell.
After the events of Doom Eternal the Slayer travels to the World Spear in order to obtain a power source for the Gate of Divum. It is revealed that the World Spear is not so much of a rock, but more of a vessel full of Wraiths in apparent stasis lining the walls. The precise fate of these Wraiths after the events of The Ancient Gods - Part Two is unknown.
They are strange bat-like creatures, with enormous wings stretched between six crab-like legs and a number of tentacles trailing from their lower body. They have a somewhat human-like head, but lack most features, only having a large mouth and a set of ram-like horns.