Arthur/Merlin, BAMF!Merlin magic reveal

[gimmemypickle]

Hello!  I'm looking for a specific Arthur/Merlin story where a villain (possibly a sorcerer working with an enemy kingdom?) tries to hurt Arthur, and Merlin is very unamused.  He threatens and/or destroys everyone that dared to hurt Arthur and is very BAMF-y and scary.  Arthur is amazed and bows before Merlin, but Merlin thinks Arthur is bowing because he's afraid of Merlin's power, and Merlin absolutely doesn't want that.  It makes him ill to even think of Arthur cowering before him.  Also, I believe it was on the kink meme and had a happy ending.  Any help would be appreciated.  Thank you!

I looked around the comm and didn't see a similar search, but apologies if this turns out to be a duplicate.