"Two months after coming to Tokyo
a ghost started to reside in my room."
This is a good one. It's a soft and sweet romance between an otaku and a ghost (well, sort of, but that requires a spoiler-y explanation so I encourage you to read this story yourself). I like the idea that only the otaku, Iku, can see the ghost, Mimori, like his Otaku-ness grants him some kind of ability to mix fantasy with reality in daily life. I also like that he doesn't like to talk to people, but he's fine with a ghost moving into his apartment.
gave me encouragement with his super-refeshing and handsome smile."
The two of them get along well, and spend a lot of time in Iku's apartment watching anime and reading manga, but every night Mimori goes back to the bridge where Iku first found him and "relives his death" by falling over the railing and disappearing. He has no memory of doing this, and of course this all greatly disturbs Iku and makes him instantly possessive of his poor l'il Casper.
"... I got
sent off by a ghost with a cucumber."
They're domestic life is adorkable and the story moves along without much happening as the two young men gradually draw closer until the BIG REVEAL in chapter 5 which, yeah, let's be honest, might be a little too ridiculous for some people to accept as an explanation. But, hey, ghosts, that makes sense, right?
"I must think deeply about this topic of death"
But, yeah, the manga is super-fluffy, despite its heavy topic. And it's filled to the brim with feels. There's also a sequel, 23:45 RE, which I'm going to read next!