AVClub: There’s really nowhere to start here other than with Maisie Williams’ performance. Her work in last week’s “The Girl Who Died” was very good, bringing nuance and humanity to what in lesser hands might just feel like just another random historical character with hints of deeper mystery. But her work in “The Woman Who Lived” is an order of magnitude better, if only because she is asked to do so much more here than she was last week. The Ashildir of “The Girl Who Died” falls into one of my favorite categories of Doctor Who supporting characters, the goodhearted ally who believes in the Doctor even as they never quite see eye to eye. But this week’s Ashildr—to the extent she even accepts that name as her own—is a character very nearly without precedent in Doctor Who history. No, she’s not the first immortal we’ve met, something the Doctor makes explicit with his reference to Captain Jack Harkness, but what sets Ashildr apart from the likes of a Captain Jack or even a River Song is that her extended lifespan is her only special ability. Without infinite memory, infinite life can mean nothing to her but constant loss: of those she cares about, of the knowledge of her own experiences, and ultimately of who she actually is.