Bloodstained: Ritual of the Night/Livre Ex Machina

Library
Below the warp room is a library that is overseen by a vampire named Orlok Dracule (O.D.). Books can be borrowed and returned. If you go the room below O.D. with the Invert shard, you can use it on the small opening in the ceiling to launch O.D. up in his seat. This gag is a reference to a similar one in Castlevania: Symphony of the Night. When you go back down, a chest will appear with the Nose Glasses inside.

Celeste's Room
To enter Celeste's Room, you first need to acquire Celeste's Key. Starting from the warp room in the Hall of Termination, go to the top of the next room. The center of the ceiling is breakable and reveals a hidden room. The middle chest contains the key.

Celeste's Room is located near the top save room in Livre Ex Machina. Inside are several music boxes that you can open and close by pressing. There are also two chairs and if you sit in one of them, a ghost will materialize sitting on the other.