The Multiverse:
The origin of the Multiverse is a complicated one. Originally, in what was known as Reality Prime, a race of beings evolved into a superior race of energy beings - hyperspace beings. They were called the Progenitors. As they evolved and grew more powerful, they built a device called Centerpoint to create more realities, deciding to play god. Centerpoint, while in Reality Prime, existed outside reality and could monitor all realities as they were made - once the process began, it continued without the aid of the Progenitors.
The Progenitors were content to watch the realities for information, but a splinter group of them wanted to do more - they wanted to rule the realities that were created as gods. The war of idealogies led to both sides battling and splitting off, with the radical group moving into the realities and vanishing from radar. Due to the fact time moves differently between realities, they evolved differently - as the Progenitors became more hyperspace like, the others became dark and corrupted, and became known as the Dark Ones - they could use the souls of the dead, and tap into unlimited power. This led to an actual war across the realities as the Dark Ones desired Centerpoint to rule the Multiverse. In order to hide the crystal station from the Dark Ones, the Progenitors sent it out into the Multiverse to wander from reality to reality. The war in Reality Prime waged on and left it decimated and lifeless.
A few things, however, came about from this war, as both the Progenitors and Dark Ones seemingly went extinct. Each of them programmed failsafes into the realities to ensure their return. In each reality, two Progenitors would be born at some point to help usher in a new era for the Progenitors - one was royality, the other was to protect them. The Dark Ones inserted a failsafe in the forms of Atheos and Theos, the devil and 'god' to wipe about the reality and bring about a 'paradise'. However, the real purpose was so that if the inhabitants of the reality were strong enough to beat them, it would ensue that fewer and fewer babies would be born until the reality went extinct from lack of a new generations, forcing the older generations to use Centerpoint to create a new reality that would allow the Dark Ones to try to hijack it.
The first encounter with Centerpoint from the inhabits of the reality where The Alien Wars 1-3 took place in The Alien Wars 2: The Galactic Conflict. The hyperspace being Wind had taken the form of one of the heroes' - Death Star - and had amenisa, believing himself to be the reploid he was impersonating due to a glitch after encountering him. The met Chronos, a guardian of Centerpoint, left behind to protect the multiverse, claiming one of them would be his replacement. However, Chronos really wanted to wipe out the failsafe designed to take over his job of protector, and began to try to rule the multiverse by first destroying it, then rebuilding it in his image as a god. The team managed to defeat him, but not before the multiverse was wiped out except for their reality and one other.
Later, Wind was driven insane by a corrupted Garland Hianule who had found a mystical reality bending sword called the Emerald Sword. Wind traveled to a third reality that had formed from their reality, and used a tri-attack to bring forth Centerpoint again, attempting to remake all three realities. The three realities battled him, and ended up defeating him, then Garland Hianule, but the result left only one reality left - their own.
In The Alien Wars 3, the Dark Ones' failsafe Theos and Athos were set off, and the team defeated them, resulting in their reality slowly dying over thousands of years. Wind, now knowing his true identity, discovered Erevis, the second Progenitor in the reality - and the royality. Her memory also gone, Wind used her to help him create a timeline divergence that temporarily created two timelines, enough to grab the energy of Centerpoint as the two timelines reconverged. Using it, Wind made a new reality, the reality of The Alien Wars 4.
The Dark Ones' hijacked Wind's creaton process, and what resulted was a long battle against them by a new generation of heroes made in the image of their previous selves in the other dead reality. They also had to battle Wind, who had gone insane due to the fact this reality had been corrupted and his desire to make a new reality by wiping out the current one. Erevis, once again born into the reality, aided the team. What ended was Wind's defeat at Centerpoint, but Xevil, having gained the memories of his former life in the previous reality, recreated the multiverse using the reality powers of Centerpoint; the team defeated him, but later would have to face what his actions had caused.
As their reality's life force crystal was stolen by others from another reality, General Cheryl and some heroes went through the realities to get it and her son back. They discovered a massive Multiverse being corrupted by some black goo that engulfed anything it touched, and a resistance group against it - the same ones who stole her son and their reality's crystal. Seeing the group was no better than what they were fighting, the team battled against them when the group's plan was to destroy many realities to halt the advancement of the corruption. However, unable to save her son, and having the corruption overrunning, Cheryl went back to their reality and used the seven crystals to bring back Wind. Together, they went back to a key point in history - the battle at Centerpoint where Xevil made the multiverse, and they defeated him before he could make it. From there, the team recreated the multiverse - effectively erasing the old one with a new one, and creating a timeline divergence from their actions so a new reality was created where events after the Battle of Centerpoint changed, including the fact her son was never taken.
Wind then sealed the three realities - the Prime Reality where Cheryl was from and the main focus of the story of the RPG, the Alternate Reality that formed from events changing after the Battle of Centerpoint, and the original reality Wind was from in The Alien Wars 1-3. However, he used his power to breathe life back into the old reality that had died out after the failsaves Atheos and Theos, and brought back all his friends, and it became knwon as the Classic Reality. Together, these three realities are separated from the rest of the Multiverse.
Prime Reality:
This reality is the one with the new generation of heroes from The Alien Wars 4 and the location of the major focus of the story in The Alien Wars 5 as it is the one where both the EarthGov Military team is located in as well as the PAX diplomatic team. It is also the location of the medieval world Tareh. Though the Classic Reality is older, the Centerpoint power is located in this reality, hidden away by Wind so that it can only be used in case of an emergency; only him and Cheryl have the power to reveal it.
Alternate Reality:
This reality is what resulted from Cheryl's actions in the finale of The Alien Wars 4. Its history is the same as the Prime Reality up until The Battle of Centerpoint, where instead of Xevil creating the multiverse and Xanatos Durran dying, the team made the multiverse and took out Centerpoint in it. From there, events began to change, such as Xanatos never becoming Legion and Erevis never being sent into a timeloop, nor those who died at Legion's hands never dying.
Classic Reality:
This reality is the one from The Alien Wars 1-3. After Wind brought everyone back to life, he set the time at the exact moment after the new Hunter Station was built, essentially picking up things right where they left off story wise.
Wonky Medieval Reality:
One of the realities in the multiverse where The Alien Wars 4 characters were all medieval knights and heroes is tied tentatively to the trinity of realities in the form of Zephyr, who has it's reality crystal in her chest, allowing her access to the reality. It remains to be seen if this teether to a strange joke reality where Drasek is a Dark Knight and Aya is a princess will have any bearing on the future of events. It is not considered part of the three realities tied together, since so far only Zephyr can access it in her dreams.