The Four Horsemen of the Apocalypse (Omniverse)

The Four Horsemen of the Apocalypse are one of the the primary antagonists in Chapter 5 of the series: Power Rangers: Omniverse.

Biography
The Four Horsemen of the Apocalypse are a quartet of immensely powerful entities that personified the four prime concepts that drive the Apocalypse.

They can manifest a human form, which can be harmed in manners identical to humans. They are respectively known as: War, Pestilence, Famine, and Death.

Each use a special ring that channels their core ability, without which, their physical forms are lost, excluding Death. In modern times, they each travel in a car (colored to resemble their steed's color in lore).

After the rise of Lucifer from his cage in Hell, he took command of the Horsemen and directs them in enacting his genocide against humanity. Their rings, unknown to all but a few select individuals, forms the key to Lucifer's Cage in Hell, and thus the Horsemen are among those capable of sending him back to his imprisonment.