Listen people you have all been bamboolzed.
Think about this manga for a second. When stalking Rei going to meet Kyouko, Haruot just
happened to have a slinky evening dress
in mahoro's size in his bag. He just
happened to know exactly how to fix Mahoro's hair. He just
happened to know where Rio was going. He just
happened to be at the family restaurant in position to stop Mahoro was tipping her hand too early.
He also just
happened to be at the party, just
happened to stop over for Mahoro's birthday party at Momoka's. And he Momoka just
happened to come back right as Rei was attacking Mahoro.
That is a LOT of coincidences.
But they aren't coincidences.
This has all been a long long Keyzer Soze plot by Haruto to make Mahoro completely dependent on him, and you all fell for it just like she did.
The real villain isn't Rei or Rio. Its Haruto, the one who's been pulling all the puppet strings to set all this in motion.
I really hope that romance isn't what's happening here, but it could be said it was kinda hinted there was some tension between them.
Oh my sweet summer child...