Emma Gilbert is one of the main characters who became a mermaid in the Australian television series, H2O: Just Add Water. Along with Cleo and Rikki, Emma discovered her powers after her trip to Mako Island.
Vote which fictional character would naturally fit in-universe with a big-named franchise! No time-travel, no interdimensional crap, no "Pooh's Adventures", they would just exist in-universe.
