This one is by candle_beck and it's also not on AO3 (as far as I can tell).

Falling Down with a Pure Heart

I am ~living proof you can enjoy this without knowing anything about canon.

candle_beck's voice and performance style make you feel right like you are inside the world of the story. I literally listened to this three times the first week I downloaded it and I don't think it's left my phone since.