Quirk
Liquefaction
Her quirk allows her to transform any part of her body into liquid. Because of that, she can stop to feel the physical pain, and it increases her flexibility and speed. Nevertheless, she is obliged to let one part of her body at his origin.
However, this quirk has some default. If she abuses of it, it can be very dangerous. The fact that she transforms herself in liquid can damage her organs severely, and the more part of her body is transformed, the more she loses stamina and falls unconscious. Sadly, it happens frequently. And the problem for Shiro is that she is not strong physically, so, her quirk is her biggest feature.