The VG Resource

I read the rules about this forum to make sure Fan Fiction is allowed, and I couldn't find anything specific. I'm assuming Fan Fiction is a part of what this creativity forum is meant for, so if I'm mistaken, I apologize.

Bowser, finally realizing he cannot succeed with his plans without first getting rid of Mario and Luigi, puts together his most diabolical plan yet. It will take a large army and a lot of magic in order to succeed. Which is just what Bowser has. Meanwhile back at Peach's castle. Mario, Luigi, Yoshi, Wario, and Waluigi along with Peach and the Toads of the Mushroom Kingdom have gathered to celebrate Mario's 25th birthday. Suddenly, a large dark cloud covers the sky, and Bowser's giant airship emerges from the darkness. Along with it comes an army of goombas, koopas, and shy guys. Bowser arrives in his clown copter and Kamek, Kamella, and the rest of the Magikoopas use their powerful magic and cast a curse on the citizens of the Mushroom Kingdom. Suddenly all of the Toads' eyes begin to glow red, and they begin to grow sharp fangs. They all head towards Mario, Luigi, Yoshi, Wario, Waluigi, and the Princess. Everything seems hopeless until Waluigi finds blocks containing feathers and leaves, and a sling star nearby. As they escape, they catch glimpse of the evil Toads attacking and destroying the castle, while stealing all of the stars. The Sling Star sends them to the Comet Observatory, but no one is there. Our heroes fear the worst has happened to Rosalina. Eventually, they find her hiding in the engine room, where she tells them that the Lumas have been affected as well. Without the Lumas' magical power, Rosalina is powerless. When the evil Lumas find the gang, they flee to the nearest Sling Star that leads them to Yoshi's Island, where they build a bomb shelter to plan their defense. They do not have much time, though. Wario suggests that they will need to search for Stars to give them power to break the curse. Yoshi will be in charge of training and leading the dinosaur and Pianta army. Wario, Waluigi, and Rosalina will stay behind in the bomb shelter to create machinery, catapults, and other deefnse weapons. Mario and Luigi will collect power-ups for the army and search for stars to restore the magical power of Rosalina.
To be continued!
If you plan to use this story as a plot for a fangame, feel free to, but make sure to give me credit.

As for sentence structure and whatnot, you are using a lot of periods where commas could easily go, creating sentences that are only about 6 or 7 words long. It makes it pretty awkward to read, and feels rushed overall.
Paragraphs are your friend, I got lost a couple times reading this.

Characters, the fact that wario and waluigi are at their enemies birthday party bugs me, let alone that they are helping after they get attacked and not running away like they do in every game ever.

You use "suddenly" twice really close to each other and it's not a good idea to use the same word like that. There's a string of sentences structured like...how do I put this

Subordinate clause, independent clause or whatever on earth you call these

"Eventually, they find her hiding in the engine room, where she tells them that the Lumas have been affected as well. Without the Lumas' magical power, Rosalina is powerless. When the evil Lumas find the gang, they flee to the nearest Sling Star that leads them to Yoshi's Island..."

When your sentence patterns repeat each other like that it starts to sound kind of robotic so it's good to create variation

There's also no dialogue. Dialogue in Mario things tend to be...rather silly and plagued with bad accents, but without it the whole thing feels lacking

the thing that bothers me the most is that it's more like a documentary, where you're just stating everything that happens, which kind of leaves the story lifeless. Another major thing is that tying a bunch of characters (even if from the same series) into one thing as if everybody knew each other in the first place. Rosalina, for example, was what I call a "one time" character, where they usually don't make reappearances, and usually shouldn't, because they really only work in their game and sound awkward in other games, unlike luigi, peach, toads, and bowser (grodus, cackletta, mario's partners in paper mario games, etc.)