I’m trying to remember the name of a manga I read where the main character is a boy who falls off his school roof and gets saved by a supernatural girl. She’s not human, more like a spirit or god-like being with mysterious powers. The boy lost his mom, and he has memories of her, especially the scent of her scarf that smells like cherry blossoms. The girl also has a scarf that smells the same, which connects her to his memories of his mom.

The boy has to hide the supernatural girl from his older sister, who acts as his guardian after their mom passed away. The sister doesn't know about the girl, so the boy has to keep her a secret while dealing with spirits and demons.

The story is kind of episodic, with different adventures, including one where they have to exercise demons in a library.