I've watched the anime first and then I decided to read the manga, and the part Kasuga moving and start a new life is the arc I enjoyed the most, not because there is barely no Nakamura, it is because Kasuga and Tokiwa, little bit different to other romance manga scenes, but this is just pure satisfying, how Tokiwa supports Kasuga mentally and so does Kasuga, I wish this manga doesn't end at all, it's too good, too enjoyable, through bad times or good times, this manga is satisfying as hell for me.
Yeah, this is a horror manga, not romance, I'm pretty sure the author decides to mess with reader's emotions, maybe it'll end up with Tokiwa and Kasuga breaking up or flower of Aku revived and haunt Kasuga and he end up hated by Tokiwa, or maybe Nakamura decided to interfere with their relationship, or even worst, let's say Nakamura psycologically manipulate Tokiwa and turns her into a psycho like herself, pushing her mentally, or Kouji, Tokiwa's former boyfriend, hire some gangs to beat up Kasuga.