"The movie would be about a lousy fisherman Wars which is a village outcast signing a pact with an evil sorcerer named Boggin Gribov to capture a mermaid, he finds a mermaid named Sawa nd falls in love with her but Boggin wants to get her for her blood so he can make an elixir to summon a demon named Bies."
If that description was real, it would mean that the character of Boggin Gribov vas partially changed into Dr. Facilier from Princess And The Frog - both being seemingly normal townspeople that happen to know local magic, but in reality doing demonic things. The movie would propably use a slavic mythos to make visuals like giant forests or swamps, but only few pieces of concept art exist to confirm this. The villain was supposed to sing a song about his powers, and some of the lyrics got leaked back in 2008:
"They tell me i am such a bad boy!
They say im evil!
But what do they know?
I know how to talk with ma' spirits!
Wars will to me come!
Then i will rule the show!"The lyrics seem to be very rough and unfinished. It is unknown why the movie got scrapped, but its presumed that its because it was going to be more adult, and any Disney attempts at making a more adult traditionaly animated flick (Atlantis, etc.) were doing pretty bad at the box office and critical reception, so Wars and Sawa got scrapped in favor of more child-friendly Princess And The Frog.
Some YouTube users, one blog (Disney Concepts or something like this...), etc.