The Burning God (The Poppy War, #3)

by R.F. Kuang

But the fact that his life was at stake lent an edge to her fighting. It made her sharper, warier, less likely to take risks and more likely to strike hard and fast when she could. She no longer fought from pure rage. She fought to protect him—and that, she had discovered, changed everything.

Rin had spent so long hating how she felt when she burned, hating her fire and her god. Not anymore. She could admit to herself now that she liked it. She liked letting her basest instincts take over. She reveled in it.