In his final days, the White mage had a suspicion that something dark was coming so he set in motion one last master plan. Since there was a chance that he wouldn't be around to oversee the plan himself, certain pieces were made to only activate under specific conditions and only at the right times. If a great evil threatens the world then what is one of the best ways to counter it? Easy, travel back in time and prevent the evil!
After an unknown amount of time doing research by the White mage and countless separate events being triggered, the moment arrives for his plan to activate. A powerful relic from another dimension (Antellion) bends time and space, which then traps the Black Mage as if his seal had just been made by the legendary heroes! But there is a problem. The relic was only a small fragment of something much bigger and as a result, the Maple world was not changed back to how it was in the past but instead got shattered and warped during the new sealing process. The Black Mage had been utterly defeated but Maple world would be changed forever. It was a victory but at what price?
Maplestory splits into 3 or 4 game universes. (worlds)
Maple central - A heavily stripped down version of the world we know. The major landmarks are the same but the geography and mobs are all changed.
Grandis, Versal and maybe the new Krakia - Mostly unexplored and only limited information available.
Each account selects one character to be its "main". This main character is able to travel to any of the universes via the dimensional portal. Each universe is a separate entity that must be logged into individually. A players character data remains the same but where they can go is adjusted. You can only be logged into one universe at a time but can freely jump between them at the world select screen.
Parts of the Maple multiverse could get updated independent of each other. Maple central would already be large so it might not need as many updates whereas Versal might get a lot more.
The greatest threat to Maple world is stopped and the remains get divided into smaller bits that should operate with far less lag. This could be the ultimate plan of the White mage.
If the White mage knew what he was getting himself into then what makes you think he would not have one or more back up plans in case something went wrong?
Luminous? What does a future legend character have to do with what the White mage does in the past? Any content included in the game can be called canon until it gets removed or altered. If I got a lore reference wrong then I would like to see the source of the claim so I can make the update intro better.
The specifics of what chunks Maple world could break into and how many there could be are yet to be determined. I wouldn't rule anything out except what was written in the story.