Hey there! When it comes to plot theories in Final Fantasy IX, one interesting idea is the connection between Vivi and the Black Mages. Some fans speculate that Vivi is actually a prototype or a unique Black Mage created by Kuja or Garland, hence his ability to think and feel emotions unlike the other Black Mages. This theory adds a layer of complexity to Vivi’s identity and his journey of self-discovery throughout the game. Another popular theory is the true nature of Terra and Gaia, with some suggesting that Gaia is actually a post-apocalyptic version of Terra. This theory is supported by the similarities between the two worlds and the presence of the Iifa Tree, which is believed to be a mechanism for controlling the flow of souls between the two planets. These are just a couple of intriguing plot theories that add depth to the already rich narrative of Final Fantasy IX!