Asuka Kazama is introduced in Tekken 5 and she has returned for Tekken 5: Dark Resurrection, Tekken 6, and Tekken 6: Bloodline Rebellion. She is mostly known to be the cousin of the series former protagonist and lead character, Jin Kazama.
Before releasing the game in the Arcades, franchise developer Namco released images of three new characters as part of their Tekken 5 promotions back in 2004. Amongst the new characters were Asuka, a Chinese kenpo master named Feng Wei, and a mysterious ninja named Raven. Immediately afterward, speculation began to spread about Asuka's role in the story and her possible relation to Jin Kazama.
Asuka is surprisingly brash and arrogant. Though, her profile states that she breaks up fights regularly, she seems to have no qualms about fighting herself and even seemingly revels in it. In her story mode, after defeating her target, Feng Wei, she decides to remain in the tournament in order to "have fun". Her pre and post-match quotes also demonstrate her confidence. As stated in her Tekken 5 / Dark Resurrection prologue, Asuka is also known as being a "nosy kid" who likes to solve other people's problems, "usually by knockout".
It is also worth noting that Asuka speaks with a very heavy Kansai Japanese dialect (Kansai is a region of western Japan encompassing the cities of Kyoto, Osaka, and Kobe).
One awkward bit of fan speculation addresses a potential romantic relationship between Jin and Asuka Kazama, which several fans have formulated after viewing the circumstances of the two cousins' first encounter. However, there is little to suggest that such a pairing may actually occur, despite the conditions of their meeting often used as a setup for many romantic couples in several popular forms of Japanese media. She is the rival of Emilie "Lili" De Rochefort, or simply Lili.