The Death Seed was an artifact of great cosmic power that was created by the Celestials. Its origins were traced to the early history of the universe when the cosmos was created. At the time, the Celestials began experimenting with creating a servant to their will which led to the rise of the Exterminators. These creatures, however, turned against their creators leading to their banishment in a self-contained universe to serve as their prison. Despite the failure, the Celestials once again made use of the power to forge the Death Seed to serve as a tool for evolution. Once imparted on a host, they gave their user a power that rivalled the Phoenix Force in its transformative potential. These cosmic relics were provided by the Celestial Gardeners to select Evolutionary Caretakers to serve the cause of guiding the evolution of a new species. At some point, the ancient Mutant known as Apocalypse who was charged with guiding the evolution of his species as dictated by the Celestials will. During each incarnation of his Horsemen of Apocalypse, he selected an individual to take the role of Death with these being a host to the Death Seed. This not only empowered its user but also provided an heir should the reign of Apocalypse ever come to an end. Among those Archangel who was deeply affected by the experience as a Horseman of Apocalypse.
When Apocalypse was killed by Fantomex, the Death Seed within Warren Worthington III activated leading to him being transformed into the new Evolutionary Caretaker of the Mutant race. A group of Horsemen selected by Apocalypse in ages past served him in this time with one among them being Sanjar Javeed who acted as Death. He would be killed by Wolverine's X-Force leading to Archangel going before the Dreaming Celestial to request a new Death Seed which he intended to place within Psylocke to transform her into the new Death. However, the Jean Grey from the Age of Apocalypse reality managed to purge the Seed from Braddock's body. In the aftermath, Genocide who was the son of En Sabah Nur intended to claim his heritage by becoming the new Evolutionary Caretaker. To that end, he called forth a Celestial Gardener in order to be provided the Death Seed and cosmic armor. However, the Apocalypse Twins, Uriel and Eimin who were the children of Pestilence opposed him where they murdered the Celestial. This started an event that was believed to affect the entire Earth as a result.
Age of Apocalypse
Within the Age of Apocalypse, En Sabah Nur himself was slain leading to Weapon X taking on the role of Evolutionary Caretaker in an effort to spare his world from the Celestials wrath. Thus, he restarted the campaigns of extermination perpetrated by Apocalypse against the human race after being corrupted by the Seed. The mainstream Earth's X-Force led by Wolverine had arrived on this world in the company of Dark Beast in the hopes of finding a Life Seed in order to cure Archangel of corruption. This brought them into conflict with Weapon Omega who had acquired a Death Seed and intended to implant it within his love, Jean Grey but failed due to X-Force. Afterwards, individuals such as Doctor Doom managed to determine the power of the Apocalypse Force with them seeking to harness it. Von Doom managed to create a device capable of storing the Apocalypse Force from its host body and empowering it within a new user.
The X-Terminated were responsible for stealing the technology and killing Von Doom whereupon they employed the technology for use against Weapon Omega. Jean Grey was ultimately responsible for removing the power of the Apocalypse Seed within her former lover whereupon it was placed within a storage device. Whilst stored, their world was invaded by the Exterminators who were newly freed from their universal prison and intended to devour the entire multiverse. It was quickly learnt that the Apocalypse Force was an anathema to the creatures as their own energies were used in its functioning. To that end, Prophet had Jean Grey find the storage device and release the Death Seeds power in the hopes that her prior experience wielding the Phoenix Force would allow her to resist the corruptive power of the Apocalypse Force. Initially, Dark Beast stole the storage device and attempted to empower himself but failed. This allowed Jean Grey to free the energy and have its power within her which she used to battle the Exterminators whilst the Age of Apocalypse was sealed to serve as a prison for the cosmic predators.
The Death Seed was created by Uncanny X-Force writer Rick Remender.