How do I get items from extra slot into the right backpack?

Question

which is the category of items from extra slot? like moon mirror , scarab ocarina? i cant get it to the right backpack when i change it >.<

Answer 1

Their category is decoration. Yeah, it doesn't make much sense, but that's how it is... Other unwanted decoration items may end up in this backpack, but unfortunately there's nothing you can do about it.