Fighting alongside biological puppets

Hello! I know this is a long shot but I'm trying to find a book I had read about 10 years ago. From what I remember, the premise was that humanity had somehow regressed in terms of technology due to some malicious AI they had created themselves (Which may have been called a Djinn if I remember correctly, though this plot point wasn't heavily explored in the first book) and become trapped on some island/continent walled off from the rest of the world by an unnatural fog. The main character is a nobody from some backwater village who is sponsored by a well-off handler to control these biological gladiator puppets through footwork and movement, fighting alongside them for sport. The main character ends up falling in love with his sponsor's daughter, which from what I remember isn't recieved well.

I believe the cover depicts the MC alongside his puppet, swords drawn.

If anyone could help me find this gem, I would really appreciate it!