Travel around the area and find Avatar in one of the coffins (his coffin location is randomized).

You will find yourself in a dark area with large amount of Undead Heads and Undead Eyes and nine coffins. The keys you'll need to press are D, A, A#, G, and C# (2nd white key, 6th white key, 5th black key, 5th white key, and 1st black key). If you have Peachone and Ebony Wings ( Vandalier and Cosmo Pavone's birds do not count), the birds will show you which keys to press. Kill The Trickster and interact with the piano. Travel very far right past the Gold Ring, until you see The Trickster in front of a piano.

After clearing Eudaimonia Machine by defeating the The Directer and obtaining Greatest Jubilee, enter Inlaid Library with inverse mode toggled on.