(The Fernsworth kingdom. The green kingdom in a fantasy world).

Muzan was sitting at the table and was filling out the report. He's a librarian of the 'Vade Mecum's Library'. This library is named after the royal scientist. It's famous by its huge amount of books and its visitors: public figures, famous scientist.

Today you came here to return books.

"Hello. What do you want?"

He said with disdain. Muzan is often quite suspicious to such 'pleb' like you.