She's basically Hayate's annoying little sister that Ryu being a good best friend has to bail out of shit all the damn time. Other than that he doesn't give much of a fuck about her, especially not romantically. Hell, he seems to like Ayane way more from the way they interact.
But since they put Irene back in all of this is moot because nobody else has a hope in hell.
I woudln't mind Ryu having love relationship with Ksaumi/Ayane/momiji. But not Irene....I know she was the main heroine from the beginning but no...not her..