Looks like the made up PM game fixation isn't stopping, because now I have a plot/villain!

One day, Bowser had Kammy use her magic on some power ups to see if they could fand a better means of using them against Mario. Just as they were starting, a small sprite known as a power up guardian appeared (I'll just say her name is Powlin), sensing their misuse of the power ups. She told them to stop what they were doing, only for Bowser to casually flick her away. She ended up landing right in the path of a magical blast that Kammy was using on the power ups. The dark magic that was meant to corrupt the power ups ended up corrupting Powlin instead, twisting her and ultimately transforming her into "Powrupt". Powrupt began creating corrupted power ups that she used to change all of Bowser's minions into her loyal followers (Bowser included).

Later she came across Mario and Peach. She had heard of Mario before and knew he might be trouble, but she also knew how clever he can be. She decided to instead us one on the Princess to have her fight Mario, knowing that he couldn't fight back. However, while it did physically change the princess, she was too pure and heavily soaked in plot armor for it to take hold of her. Powrupt realized this could be trouble and sent some minions at them as she made her exit for the time being.

After beating the low ranking troops, Kammy appeared, having fled Bowser's castle after Bowser was transformed. She explained that Peach wouldn't be able to turn back into a human unless Powrupt was purified, and to do that, Mario and Peach would have to collect the 7 Mc Guffins.