Looking for a movie?

Hello, I'm looking for a film. I can only partially remember the end. There's a group of young people from a medieval town, I'd say, which is protected by a barrier. One of them puts things on everything outside the town so that this area belongs to his company because they were all greedy. Meanwhile, the girl goes to the last dragon. They talk to each other and then she stabs him in the heart with her sword. He multiplies and then the dragons attack the town and they keep multiplying when they die.