Rise of Immortus (Earth-21)

"Immortus is rising, and just like everything else in the godforsaken universe, it all leads back to you lot."

- Willoughby Kipling to the Doom Patrol

The Rise of Immortus is the Agents of Immortus' quest to extract the pieces of General Immortus from members of the Doom Patrol, reverting them into mortals once more.

Immortus Project
Since the early 20th century, Niles Caulder of the Bureau of Oddities had been searching for a method of obtaining immortality. Caulder had hoped to achieve so in order to spend more time with his immortal daughter, Dorothy Spinner. This project soon led to the discovery of General Immortus, who Caulder extracted pieces from and created a necklace to immortalize himself.

Doom Patrol
In possession of the pieces, Caulder began selecting different methods of immortality as well through causing deliberate accidents. This gave him access to Rita Farr, Larry Trainor, Cliff Steele and Kay Challis. Caulder transformed the four into metahumans with special abilities, and placed pieces of Immortus in them. This was left unbothered for decades, until Caulder passed away due to old age, a result of him trading his necklace to restore the Doom Patrol to full size.