There are multiple parts of the manga that I remember.
One of them is about a ghost that hit on a woman. They were in a bar, a woman was drawn to the jokes and stories the ghost was telling. They then got into a hotel and started making out. The main male barged in, saving the woman from the ghost. The ghost then possessed him. Things happened as he went to school. The female main noticed something was wrong and confronted the ghost. They went on a train together ( I forgot why and where). In the hotel that they stayed in, the girl managed to get the ghost out of the boy's body. This is as much as I can remember for this one.
The other story is about a gremlin, lizard-like man. He was staying with the male main for the time being. One day, the girl came over and he was interested in her and followed her back. The girl noticed. They came up with a plan, pretending to have sex when the boy came over, to draw the man out. I don't remember how they resolved his problems, just the first part.
There's a story about a woman with hatred and regret. A story about a giant ghost. There was also the relationship the male main had with a ghost who teaches him. It's only a recollection, as the ghost had to ascend and he had to live without him (I'm not sure what I'm saying here).
What I wrote seems choppy, but I hope this helps.
