Alternate realities are different realities that exist side-by-side with one another, unable to be crossed under normal circumstances. They each contain their own histories, and may be similar to each other or completely different.
Alternate realities exist in theory, but were not proven until a comet of unique trans-reality ore crashed into Daibazaal. The source of the comet's ore and explanation for its nature remain unknown, but the ore was infused with Quintessence and able to act as its own endless power source. The crash caused a trans-reality rift to open up on the planet's surface, leading to an immeasurable amount of Quintessence on the other side. Mysterious creatures of darkness also existed within the rift, and were the only creatures able to safely pass between realities.
Voltron is granted the ability to safely traverse trans-reality rifts because it was created from the ore of the comet that crashed into Daibazaal. A second comet was located by Alfor, which he sought to keep hidden from Zarkon, but a mysterious incident led the ship sent to retrieve the second comet to become trapped between realities when a rift opened, killing all Alteans on board with its unfathomable energy and freezing half the ship in one reality, with the other half frozen in another reality. This second comet is used to create Lotor's own trans-reality ship once it is retrieved.
- Slav has done extensive study into alternate realities to the point that he is overcome with paranoia and mentions them constantly.
- The only alternate reality fully seen is one containing an oppressive Altean Empire created by Empress Allura to avenge her father and defeat Zarkon before he can begin his own empire.