If this were true, this theory becomes extra ironic considering that it would mean that Wario literally kidnapped Mona's mom, Daisy, at one point in Super Mario Land. And for anyone who's confused because Wario wasn't in Mario Land 1, the Super Mario Land trilogy on the Gameboy has an ongoing connected story across the three games, and the kidnapping of Daisy in Mario Land 1 was a scheme by Wario. The main bad guy, Tatanga the Spaceman, was actually one of Wario's henchmen, and Wario had him kidnap Daisy to distract Mario, so he could then seize Mario's private castle leading into Mario Land 2, where Mario returns home from saving Daisy and tries to take his castle back. You even rematch against Tatanga in Mario Land 2 as he is one of Wario's goons holding one of the six golden coins. So ultimately Wario was behind Daisy's kidnapping. And yet here her daughter loves hanging out with him and is smitten with him, even having stuff themed after him hanging in her room lol. The main question with this theory though would be how on earth the age and time gaps even work. Is this assuming the WarioWare games actually take place FAR into the future from the normal Mario series? Because Wario is roughly the same age as the Mario Bros. at least, so around 24, in the Mario series. So for this to work without some weird time-travel shenanigans, we'd have to assume Wario isn't 24 in WarioWare but is now in his 40s and that WarioWare is absolute MINIMUM like 16 years in the future from the rest of the Mario series, which not only is surprising because he seems pretty much the same, but also that just makes his connection with Mona WAY more questionable lol, because at least if he was in his early to mid twenties in WarioWare that wouldn't be THAT far off from Mona, who's presumably like 16 to 18.
This at least feels like it would line up with their personalities and looks (except for the part where daisy was kidnapped by Wario before), even if a little stretched. I feel like this is a neat headcanon.
9:53 And also one of my headcannons is that Wario is the third Mario brother that got neglected by his parents wait so that means that wario is mona's uncle OH GOD
Problems with the theory: Mona's dad is taller than Mona's mum in their wedding photos Mona's dad has a parted moustache Daisy is an empress, not a supermodel Mona would be in love with a man that tried to kill her uncle and also hates her father In the Japanese diary entries for WarioWare, Wario and Mona's dad don't recognise or even seem to know eachover Luigi canonically got the Rank D mansion as shown in Dark Moon Mona's dad has a small nose instead of Luigi's giant nose Mona's mum has shorter hair Just because Luigi has a painter outfit doesn't mean hes a painter. Other Mario characters have a whole bunch of different outfits, doesn't mean they have that job If the WarioWare games are in the future, that doesn't change anything as futuristic things are in Mario's time