This is a very good development. Either the cognivores did it, or old Igor's father actually turned himself into one of those monstrosities and has been possessing Ron ever since. Or it's something I haven't thought of.
Looking forward to more.
Author's response
I will neither confirm nor deny that Saha Karkaroff may or may not have, in this or another alternate universe, become one of the creatures he created in order to possess a certain Weasley. . .
Love Stolen Magic, will you be updating soon?
Hint, hint. . .
GG