Kasamatsu does sometimes find it slightly unnerving, knowing that there is a supernatural being floating around his house that he can't see.
Like - how does he know that the ghost doesn't hang around the bathroom when he's doing a shower? Does the ghost watch him when he sleeps or something?
He really hopes the ghost is a mature being.
Most the time, though, it's like having an extremely shy roommate who never shows his face but leaves his mark around. Again, it's not that bad.
But Kasamatsu is really curious, so eventually he gathers up the courage, tells himself that it's only a ghost and he really shouldn't be embarrassed, and takes a stray whiteboard pen and after spending ten minutes rummaging around his room to see whether he had a mini-whiteboard or not, he writes,
"Are you a ghost?"
Then he draws two boxes, writing "Yes" next to one and "No" next to the other. As soon as he places it on his desk before he goes to school, he feels another wave of embarrassment, but he steels himself and grabs his bag, walking out of the door.
(Since the ghost seemed to enjoy playing with his basketball, Kasamatsu had deliberately left the basketball right next to the whiteboard and the pen, just in case the ghost would miss it. He hopes that it is a ghost, because he doesn't know much else about supernatural beings and he's still under the impression that apart from a few ghosts, most supernatural beings - if they even exist at all - are probably hostile, and Kasamatsu doesn't want to be killed by an angered demon or something. He tells himself that if it was hostile, then he'd probably already know by now, but still.)
Kasamatsu manages to dislodge the supernatural from his mind when he reaches the school gates and Moriyama immediately begins telling him some story about how he bumped into a pretty girl on the way to school.
Kise Ryouta watches the black haired boy leave, hovering around the apartment door before he floats through the door back into the apartment. He doesn't feel like going outside, today, but he quickly gets bored of going through the kitchen fridge and floats over to where he knows the resident's bedroom is.
It's neat and organized, as usual (Kise has a distinct feeling that when he was alive, his room was never this tidy) but what catches his eye when he drifts over to get the basketball is a mini-whiteboard on the desk. Kise blinks at the words written on it, then his eyes move to the whiteboard marker lying besides it, and he laughs.
It's actually kind of cute.
Kise reaches for the pen, and it takes several attempts before he manages to solidify himself enough to grip the lid and pull it off. (The boy had left the lid slightly loose. How considerate.) Even as he's moving closer, he can feel his concentration breaking, so he makes a quick squiggly tick inside the box next to "Yes" and since he has a little bit of strength left, he draws a smiley emoticon next to it before the pen drops from his transparent hold and lands on the floor. Kise manages to nudge the lid onto the pen (it's too much effort to do the complicated, fiddly maneuvers of picking up the pen and replacing it onto the desk, so he leaves it on the floor, capped safely) and drifts out again, and he feels a rare excitement (was it excitement? Or just mere curiosity?) as he waits for the school day to finish.
But the thing about being a ghost is that he has a lot of time to think. And Kise doesn't like overthinking but sometimes he has nothing to do and he literally cannot help but think.
And most of the time when he overthinks, he overthinks about his past life. Who he was before.
He remembers his name, and he's tried to enter it into search engines on computers before, but they never work. It could be because he's a ghost - technology just never seems to work properly when he tries. (Which is disappointing, but at least he can still watch TV and films from a distance if it was someone else who had turned it on.) When he concentrates and tries to dig up a memory, any memory, from his past that isn't his own death, he can only see small flashes of colour, a mix of voices merging into one another as barely-there whispers in the back of his mind, and nothing else.
He does know that he played basketball, though.
Apart from that, he knows nothing. He can't remember what he looks like - he doesn't appear on mirrors, which he's always found disappointing because A) it would give a much wider range of ghostly pranks to play on people and B) he just wants to know what he looks like.
The only event he can remember clearly - or somewhat clearly - is his death. And naturally, he doesn't like reminiscing about his own death.
It was a pretty painful one, after all. So Kise tries not to think, and watches the humans on the street walk past each other in a bustle of life as the sun moves across the sky and the shadows move across the ground, and he plays a game where he guesses whether the next person to cross the street will be male or female, young or old. (It's a boring game, but it's something.) He plays the game until he finally sees a certain person heading towards the apartment.
Kise follows him as he unlocks the door, tossing his keys onto the small table, trudges through the corridor into his bedroom, and spots the mini-whiteboard on the table.