The sister has a lot going on as a character, and seems placed to contribute more in further sequels.
She’s self-taught. While Shaun was trained abusively, Xialing was ignored. On the quiet, she watched and learned.
She’s self-made. After leaving home as a teenager she built a fighting arena in Macau that becomes hugely successful. At the end of the movie, she’s taking over her father’s crime business.
It’s actually a bit awkward. She’s brave, strong, smart — a hero — yet no one ever suggests that she wear the Ten Rings. Even she never questions why Shaun gets the power. It’s canon, or it’s a father/son inheritance, or both. Shaun never even offers her the Rings. I mean, yes, that’s the story — abused boy becomes resolved man — but if sister is going to be worthy of power, then we need to see that discussion.
Oh, dear. She’s much more developed than mom and auntie, but is she just an archetype, too? What does she want? What is her arc and what are her goals? She gets a lot of screen time and is integrated into the main plot. She saves them on the skyscraper scaffolding and in the final dragon battle, but her actions could’ve been performed by anybody. Besides being Sister, she brings nothing specific to these moments. Yikes.