Slight spoilers about Kiyoka, click if you are curious (no major plot revealed)
As you might already noticed, she's a slight yan (as in yandere). She gets jealousy easily when Daito being friendly with other girls and this will get more and more apparent. There's one chapter she tortures Daito because he told her about how girls around him being more chummy with him and it was hilarious.
She won't realised her feeling until volume 10. Just FYI, we have just finished volume 4 here.
And yes, harem ending is the only true ending we deserve.