The keeper ring is ring that can be found in a locked chest in Artemus' rooms and can be used to open up a hidden passage leading up to Orland's room.[1][2]
Tips[]
I could tell you where it is, but that would spoil all the fun...
This section contains spoilers! Read on your own peril.
Stealing the ring is optional thought as the Climbing Gloves can also be used to gain access to Orland's room but getting down might be a problem. Note that it is still required to search Artemus' room for in-game objective reasons.[3]