Random Crossover Ideas

RWBY X Desolate Era

Fate had never been kind to Jaune. Wracked by illnesses and infirm his entire life on Remnant, Jaune knew early on that he would die as a teenager. What he didn't know was that there really was such a thing as life after death, and that the multiverse was a far larger place than he thought. A lucky twist of fate (one of the few in Jaune's life) meant that Jaune was reborn into a world of Immortals and Monsters, of Ki Refiners and powerful Fiendgods, a world where Dynasties lasted for millions of years. A world which is both greater...and yet also smaller...than he ever could imagine. He would have the opportunity to join them, and in this life, Jaune swore to himself, he would never let himself be weak again! The Era he was born into was a Desolate one, but Jaune would make it his era.

Locations

Definitions

Chaosworld - A vast world that is made by a World-Level cultivator. Normally has a lifespan of 1 Chaos Cycle, though can have a longer lifespan given special circumstances. A celestial body between the size of the sun and our solar system, exact size is uncertain.

A Chaos Cycle is 10 trillion years long. 

Territory - Essentially a galaxy. A group of many celestial objects - stars, moons, chaosworlds and other. The distance between territories is extremely large. Can contain an Everworld, but does not have to.

Everworld - A world created by an Eternal Emperor. Vastly larger than a Chaosworld and lasts eternally.

Realmverse - A large region within a Chaosverse that contains many territories and other secret realms and worlds. Is technically eternal, but eventually the Chaosverse will deliberately cause its destruction so another Realmverse can be born. Approximately the size of our universe. Created by the Chaosverse itself.

Otherverse - An artificial Realmverse created by an Autarch. It has its own Prime Essences based on the Daobirth Essence of the Autarch who created it, which are different from the main Chaosverse's Prime Essences.

Can be bound by a cultivator to become an Otherverse Lord.

Chaosverse - An extremely, extremely large body floating in the Infinite Void. Contains many Realmverses, each of which are separated by utterly vast distances to such an extent that a powerful Daolord, capable of travel speed of millions of times FTL, would die of old age (108,000 Chaos Cycles) before reaching the closest Realmverse. Has its own Prime Essences. Can be bound to an Omega Autarch to become a Chaos Lord.

The Infinite Void outside - even bigger. Contains many strange celestial bodies. Chaosverses are the biggest.

The Three Realms 

was the Chaosworld/Universe that was created after the destruction of the Pangu Chaosworld/Universe and Seamless Chaosworld/Universe when they collided with each other. The Worldheart of the Three Realms was created from the fragments from the two Chaosworlds/Universes. It is just one of the Countless Chaos Worlds in the endless Primordial Chaos.

Pangu Chaosworld and the Seamless Chaosworld were both created from Autarch godgems. These godgems were merely 2 in a set of 108,000 from Autarch Awakener who arranged for them to disperse them throughout the chaosverse if he failed to bind the chaosverse to himself.

Background

During the tribulation that left the Primordial World in shambles, many Daofathers and True Gods, including Daoist Threelives, perished. Nuwa, along with other Daofathers, repaired the remains of the Primordial World to some extent and created the Three Realms.

Due to the fact that the three realms was created from the collision of two Autarch godgems, the creatures that were alive during the war that ended the Primordial Era and were born during the Three Realms Era were blessed with incredible talent. The fragments from the two godgems melted away and their power was dispersed upon the countless living beings in the new world.