Like hentai, there are no disgusting characters, which is definitely +. Sex scenes, due to the "possibility of changes" - are quite interesting. But.... Again NTR in the very first series, just why? In addition, it could freely "not happen", but the main characters are "spiritual" for this.
Also the final phrase... It practically says that NTR is the norm, although what did we expect from a succubus. Kanzaki fantasized to himself and it seemed so to the audience.
