Pact of the Mask | On warlock Pact Boons and an elephant in the room

Something of an addendum to last week's Temples & Triforces, the Pact of the Mask is an idea that came to me thanks to a friend. He saw the document and then asked if I had any ideas for Link's masks in Majora's Mask. The question intrigued me; at first, I suggested a Mask Salesman subclass, or a series of magic items. But then as I continued thinking about it, I had another idea that I wanted to explore: a warlock Pact Boon.