It honestly feels like the fake Millennium Star didn't really intend to let anyone win his contest because due to having the Millennium Star's legend on his side, as long as there's no winner, he's essentially on top of the world. Notice how he barely (if ever) mentions anything about getting them out of the toy box at all, and if you go in Peach's Castle, he's basically taken over the place with multiple pictures of himself in the top floor room.

The fake Millennium Star kickstarted Mario Party 3's plot in order to essentially take over.What was the first thing the fake Millennium Star do after crashing to the Mushroom Kingdom? Trap everyone inside a toy box, then tell them that he would make one of them the Superstar of the Universe. This game's events (the contest to be recognized as a superstar/hero), along with Luigi's diary entries in Paper Mario, is ultimately a foreshadow for Luigi's Mansion.

It arguably makes more sense for Luigi to be the protagonist here than any of the other characters as at the time, they've all established themselves as distinctive characters, whereas Luigi was still largely an under-utilized, flat character.

In fact, the only Star Stamps he can't replace, Beauty and Mischief (perhaps the characteristics he least fits into out of all the Star Stamps, fittingly enough), are locked to Daisy and Waluigi, two characters sharing more significant relationships with Luigi than anyone else of the cast, and perfect matchups for him in the story mode as a result.

And after his shyness started developing, almost everything else we know and love about him came to shine later on, too, like his undeniable love and kindness, decisive strength and courage when necessary, and even unexpected wit at times - all motifs of the Star Stamps he can potentially replace.

This game also happens to be released around the debut of Paper Mario, which is when Luigi first began his overall character evolution from being 'Green Mario' into the timid, clumsy scaredy-cat we all know and love today.

He actually replaces specific characters depending on who you play as.

He is the only character who does not have a set Star Stamp in the story mode.

Luigi is the 'canon' protagonist in Mario Party 3's story mode.

Pirate land mario party 2