Wait I dont get it... the first question in the QnA is answered with that the MC is into girls?
I thought the whole theme of the manga was budding boy's love?
thats what im saying bruh plus i thought this was a bl but theres hardly been any actual BL shit where is it 😔
the human!Hikaru was into girls (though he could be bisexual but didn't realize that yet) but he clearly loved Yoshiki to some extent.
Because of the love inside human!Hikaru, when the monster/deity took over his body,
he also loves Yoshiki. But since this monster!Hikaru doesn't understand lots of human's concept and definition, he doesn't really understand or differentiate between friendship love and romantic love.
so the situation is:
Yoshiki is 100% in gay love with Hikaru. While Hikaru is fucking dead (rip), the monster using Hikaru's body is a lot like him so Yoshiki can't help but love the monster too. And the monster just likes/loves Yoshiki without caring about other things.
The story is basically about how Yoshiki is slowly accepting Hikaru's death and maybe falling in love with the monster, and the monster learning about human (to be alive, in love, that kinda thing) while also dealing with other crazy supernatural things happening around town.
I'm not a fan of BL and even I understand that this thing is slowburn. If you want some fast/easy love story then this just ain't for you buddy.