Here's Everyone Arya Has Straight-Up Murdered on Game of Thrones

In season six, Arya undergoes rigorous training at the House of Black and White, the Temple of the Many-Faced God in Braavos. She spends a lot of this time without her sight, and her prime torturer is the Waif. In the end, Arya faces off with the Waif in complete darkness. Although we don't see the outcome, it's presumed Arya is the only one who makes it out alive.