Just a stupid idea I had around 15 years ago. Thought it'd be fun to try recreating it here.
One time on deviantArt I saw a picture of an evil Saria holding a staff. I came up with a storyline of how that hypothetical scenario came to be, calling the story The Scepter of Darkness.
Basically after Link left prior to the events of Majora's Mask, eventually Saria willingly chooses to leave the forest to go searching for him, traveling all around the world in the process (and because she left the forest for more than a short while she lost her eternal youth).
Eventually she accidentally stumbles upon this staff sealing away a great evil power and it corrupts her, but not completely. It takes some time for her to fully give into it, and after Link stops her, the sequel is about him trying to save her and destroying "The Demon Within" said scepter.
I deleted these stories from the internet a while ago because I was unhappy with them, but I had fun trying to recreate this concept.