Just had a thought come to me while re-listening to WoK: What if Cusicesh in Interlude 5 is formed by B-A-M’s imprisonment? The way it faces the origin and shifts through faces for ten minutes indicates a connection to all of Roshar, and Axies indicates that it is unlike any other “spren” on Roshar.
Oh right, and it leaves everyone feeling drained. Like a (very minor) reflection of the damage done when she was imprisoned.
Obviously not a fully fleshed-out theory, but I’m interested if anyone else sees other connections.