Needy, emotionnal, boring two-timing "freeloader" that did not offer herself to Ayato or at least offer they get a single room that Ayato paid with his part-time job while she stayed in the hotel room and wrote her sappy feelings in her journal. I was so glad he ended up killing her. She got what she deserved.
I would have not had her in the ending as one that loves Ayato as her charcter made ZERO impact in the story and turns it into some type of Harem with a male lead that has no place in such a series. The series has plenty of lovely ladies and many are strong-willed and minded so such an anime mighht have been interesting but Hiroko would have been the cute "dud" of the bunch no one cares about.