Debunk Time.
Kris' Knife CANNOT be the Roaring Knight, as Kris ALWAYS carries the knife around (bc they know who the knight is and what they are doing, their knife is essential to the RK plan) meaning when they seal fountains, the knight *should* be there (according to you).
The knight is for sure a lightner, as queen says: Is this not a thing all lightners possess? (when she is talking abt "determination".
The knight is probably dess or carol, any papyrus theories are a joke.