Earth-90

Earth Ninety  is one of the many universes in the multiverse.

History
In late 2018, Mar Novu/The Monitor ravaged the Earth and then used the Book of Destiny to massacre all its inhabitants, leaving Barry Allen as the only survivor.

Residents

 * Barry Allen
 * John
 * "Captain Cold"
 * "Star Girl"
 * "Green Arrow"

From The Monitor's realm

 * Mar Novu/The Monitor

Behind the scenes

 * The number 90 is a reference to the original '90s Flash television series.
 * Marc Guggenheim later confirmed on Twitter that the 90s series actually takes place on Earth-90.
 * The dead warriors of this Earth, while not named, depict various versions of DC Comics characters. These include Stargirl, Hawkgirl, Huntress, Hawkman, the Green Arrow from Smallville, the Captain Cold from the 1990s Flash TV show, Leo Snart/Citizen Cold, and Firestorm.