@yiledute someone's face getting red doesn't always mean they may like you. There are many other possibilities, like being flustered to find a proper answer while you're trying to hide some motive.
It's been a while since I read it so I could be misremembering some things, but I believe the demon girl is long since dead. Can't really explain further without heavily spoiling things.
I do agree though, the demon girl was cute and I do somewhat prefer her to Cha, but later in the story I begin to appreciate their relationship more.
I kind of feel like Cha doesn't deserve the mc..... I would have rathered the girl in the very beginning since she was friends with the mc even before he became OP or maybe just a character who's you know REALLY POWERFUL AND SMART and not somebody who's only difference from other S level characters is her sense of smell? I'm sorry it's just my opinion, I guess I'm being over judging cause I feel that Cha doesn't really have that many qualities that make her 'different' I guess.....