Had a thought about Ghost Knight!Y/N.
Namely, that after their fractured mind put two and two together in regards to Shadow Milk being their dear Fount of Knowledge, suddenly they switch from stalking around the Spire to constantly hanging around Shadow Milk unless he actively goes out of his way to either order them to stop or avoid them.
Because the reason why they protected the Spire beyond death was to ensure their Fount of Knowledge had a home to return to. And now that he has, they can once again loyally serve and protect him, even beyond death.
It probably wouldn't take long for Shadow Milk to learn about your presence. As soon as he returns to the Spire in his newly-baked body, Black Sapphire and Candy Apple come rushing up to him. As delighted as they are to see him, they quickly tell him that the Spire is haunted!
They practically talk over each other, explaining how a spirit has been impeding all their work...how it keeps trying to chase them off! And when they tried to face it, it actually attacked them! With a sword!
Naturally, Shadow Milk isn't having this...this is his tower, his domain! He's the one who decides how everything plays out, not some...squatter spirit!
So he hovers through the Spire's halls, just waiting for this "ghost" to make their appearance. It isn't long before they do...a pale, spectral knight appearing in the middle of a room as he enters, hand already on the hilt of their sword!
...seeing that it's a knight gives him...a brief moment of pause. Though he can't quite make out its features, could it be possible...?
You approach him, slowly drawing your sword...before pausing, looking him over. Your gaze lands on his Soul Jam, lingering there for a long time.
Slowly, your form shifts...your face becomes clearer, and its unmistakably you. Shadow Milk hisses in a breath.
...after a heartbeat, you kneel in front of him, your sword propped before you. "My...Fount..." you hum.
"...my knight," he says softly, reaching out to touch your hands...of course his hand just passes right through you. But he can't help but let out a choked laugh...you're here.
Naturally you follow him around after that...perhaps invisible most of the time, unless something threatens him, but still very much there. Shadow Milk will yap to you constantly, and...I can't see him bringing himself to order you somewhere else.
He's been separated from you for so long, why wouldn't he want you at his side, always?
