Basically ex-crybaby kindergarten kid (I'll call him Ikemen) and mi-chan the ex-bully kindergarten kid went out together. She died, then remembered the one person who always defended Ikemen in their childhood (and that would be the dark haired dude) so possessed him. Ikemen started acting weird... The no homo was strong (even tho he didn't want to engage in it). Buuuuuut the charm didn't work and he was sus, in the end he started actually liking dark-haired-dude. Mi-chan gave her boyfriend to dark-haired-dude because Ikemen was starting to not see the ghost of her in their moments.
Dark-haired-dude is in the emotional state where it's not love that he feels, but it isn't an appropriate amount of liking neither... He is sus too
Plus dark-haired-dude and Ikemen had a cute past, for dark-haired-dude it seemed like he was defending Ikemen but for mi-chan it was more like a challenge about who gets Ikemen's attention
Anyways, relationship undeclared, but they want to heal one another *cough* dark-haired-dude wants to do it more *cough* but Ikemen definitely would drop his panties for that one day *cough*, they have had that dynamic since kindergarten days
I'll read the Mangaka's other works to see if there is more of this couple
Maybe I'm just too dumb to understand this manga. Yep, I'm dumb. School grades said so.