Ahsoka Tano, a young female Togruta nicknamed “Snips”, was introduced for the series Star Wars: The Clone Wars and appeared to be one of the main characters. In the course of the series she became Anakin Skywalker’s Padawan. After being framed for the bombing of the Jedi Temple, and lacking the trust from the Jedi Order, she finally left, out of disappointment. Her reckless and unorthodox personality was, amongst other things, reflected by her lightsaber style, mainly defined by the reverse grip of the Shien form and later by the use of a shoto (a short lightsaber or lightdagger). The rebellious touch of her character is probably the bridge to her appearance in Star Wars: Rebels, where she surprisingly turns out to be “Fulcrum”, an ally of Kanan Jarrus’ group. Being an adult, Ahsoka had a more serious charisma during her entrance in Rebels. It seems as if she had managed to channel her juvenile recklessness and had become a focused personality – still a rebel, though!
If you want to know more, take a look at the color-guide (costume & lightsaber) for Ahsoka Tano on StarWars.com.