#merlinfandom

I am reading lots of fics where Arthur learns about Merlin's magic and how much Merlin has done for him. And in many he feels the same, that he would do anything for Merlin, anything. Only I haven't read a fic yet where he really does. Sure there are some h/c fics where Arthur and the knights rescue Merlin, but I am talking soul-destroying sacrifices here, Arthur sinking into despair and blackness and crossing that line by miles to save Merlin. We know Merlin would burn the world for Arthur, but I want to see a well written, believable, in character fic where Arthur burns the world for Merlin. Any recs?