Worldofme

A worldofme (plural worldsofme) was a device used by the Celestis to protect themselves with an infinite number of copies.

Nature
A worldofme consisted of a hyperlink to an artificial universe entirely populated by continually-updated back-up versions of the user. Should a Lord of the Celestis die in the material universe, the worldofme updated a copy of them in the exact time and place. They could then prevent themselves from dying with the endless copies of themselves. However, the final copy that survived remembered each and every death, which could be obviously distressing.

History
Devised by the Celestis as a way to ensure themselves even further against death than their shedding of physical forms already had, worldsofme were eventually used as a military device, as seen with the attack on the City of the Saved.

Worldsofme fell out of favour after it became a widespread political tactic for one Lord Celestial to tamper with a rival Celestis Lord's worldofme so that the backup copies, once uploaded into reality, would be more favourable to the tamperer's political line. This was notably demonstrated by Lord Twin Leopard against Lord Spider Rampant. (PROSE: The Book of the War)

Behind the scenes
Although an explicit connection was never established, a 2015 episode of Doctor Who utilized a similar method of survival by a Time Lord.