Caster / Elsie Chapman.

Enhanced descriptions from Syndetics:

Avatar: The Last Airbender meets Fight Club in this action-packed fantasy about a secret, underground magic fighting tournament. If the magic doesn't kill her, the truth just might. Aza Wu knows that real magic is dangerous and illegal. After all, casting killed her sister, Shire. As with all magic, everything comes at a price. For Aza, it feels like everything in her life has some kind of cost attached to it. Her sister had been casting for money to pay off Saint Willow, the gang leader that oversees her sector of Lotusland. If you want to operate a business there, you have to pay your tribute. And now with Shire dead, Aza must step in to save the legacy of Wu Teas, the teahouse that has been in her family for centuries.When Aza comes across a secret invitation, she decides she doesn't have much else to lose. She quickly realizes that she's entered herself into an underground casting tournament, and the stakes couldn't be higher. Real magic, real consequences. As she competes, Aza fights for her life against some very strong and devious competitors.When the facts about Shire's death don't add up, the police start to investigate. When the tributes to Saint Willow aren't paid, the gang comes to collect. When Aza is caught sneaking around with fresh casting wounds, her parents are alarmed. As Aza's dangerous web of lies continues to grow, she is caught between trying to find a way out and trapping herself permanently.

Reviews provided by Syndetics

Booklist Review

The world is falling apart. Real magic, rare and potent, drains energy from the earth every time a spell is cast, leaving behind charred land, frozen oceans, and smog heavy in the air. Aza is secretly a full caster, but she hides her powers, pretending to be someone who can only do small, leftover magic. She's trying desperately to pay her family's debt to sector boss Saint Willow before goons come to bust up her home and torture her family. Stuck in the shadow of her now-dead sister, Shire, Aza has one week left until Saint Willow's people come for her parents. When a note left by an old tutor leads her to an underground magic-fighting ring, she realizes she has the chance, the power, and the skill to get out from under Saint Willow's thumb possibly for good. The fighting ring leads to more questions still, as well as more danger. Could learning the secrets of magic and the truth behind her sister's death be worth it all? Chapman (Along the Indigo, 2018) has created compelling young adult novels before, but this is a cut above; the fully realized and atmospheric dystopia is crafted at a level not seen often. This stunning fantasy will fly off the shelves.--Stacey Comfort Copyright 2010 Booklist

Kirkus Book Review

In a dystopian world broken apart by magic, Aza Wu struggles to unravel the mystery of her sister's death while fending off gangsters and dodging Scouts who hunt full-magic casters like herself.The rules of magic set up by Chapman (Hungry Hearts, 2019, etc.) come down to this: The more magic you use, the more magic you pull from the Earth, leaving behind a scar ranging from a buckled road to an earthquake that levels buildings. A full caster is limited by their level of control and the physical pain that follows a spell. Despite the dangers and the guilt she feels for damaging the world around her, Aza desperately casts magic for marks to pay off the family debt. This leads her to the underground Tournament of Casters, where she will risk her life for marks and answers. The main character identifies as Chinese, and though some racial and cultural discrimination is discussed, the story focuses more heavily on the haves and have-nots of magic and power. The pacing is fast and furious, upheld by the deadline Aza faces of a single week, which almost becomes a running joke. Some characters are ham-handed in their villainy, but most are genuine in their struggle to do what it takes to survive.A dark and, at times, vicious and violent story of will and questionable honor. (Dystopian fantasy. 13-17) Copyright Kirkus Reviews, used with permission.