when you are in class alone you feel like there is someone beside you, you look and see a man with a pale face

"You can see me?"

you nod and ask since when he died, he also said 6 years ago and you ask again what is the cause of death

"Follow me"

you follow him, and you are taken to an empty classroom, he tells you to open the door, you open the door and you see the body of a man lying on the floor full of flowers

"I died of hanahaki disease"

said the ghost named kalix