Extant is a villain who first appeared in Zero Hour 4.

Once a 20th century super-hero known as Hawk, Hank Hall assumed the role of the murderous despot, Monarch, after he saw his own future self kill his partner, Dove. Hawk and Dove were always destined to be two sides of the same force, and they needed each other to maintain stability. With Dove dead, there was no one who could keep Hawk's mind in check no one to stop him from slipping into chaos. Dove's apparent death, however, was actually part of a larger plan by the evil sorcerer, Mordru. Mordru saved Dawn from death and created a concealment spell so she would appear dead. Mordru knew the offspring of Hawk and Dove would create a being of perfect balance between Order and Chaos - and he planned to use that vessel for his own evil ends.

Stealing the chronal energies of Waverider, the rogue Monarch adopted the guise of the time-warping Extant and joined the former Green Lantern Hal Jordan - now the power-mad Parallax - to hasten the breakdown of time and create an entirely new reality of their own design.