Bill has an extraordinarily quick mind but also an odd way of comparison – she calls the TARDIS “like a kitchen” when she first enters it, but goes on to build strange, offbeat, but correct conclusions about the Doctor each time she encounters new information (she wonders why he left it as a “Police Box,” and intuits that he sees himself as the policeman for the universe; call him, and he’ll come rescue you; when she realizes she’s “speaking Latin,” she immediately suspects it’s either the Doctor or the TARDIS, with some sort of “translation program”; she figures out he lied when he told her he could fix her as a Cyber Man). In their initial encounter, when the Doctor asks her why she attends his lectures even though she doesn’t attend the college, her explanation has nothing to do with his original question! (Sorry, her brain just went on a tangent.) She tends to go for the fantastical explanation over a sensible one, but also is, again, correct (“I’ve seen movies, I know what a mind wipe looks like!”). She loves to theorize about and experience new ideas and things. Her inferior Si shows in her willingness to abandon everything she knows to explore the greater world, but also a tendency to want to be cautious when she encounters too much danger (“I’m with Nardole, let’s go back to the TARDIS!”). Her Si helps her defeat the Monks, when she’s able to draw upon a “made up” memory so subjective they cannot pollute it. Bill constantly asks questions and gets sidetracked in all the logical impossibilities everywhere they go. She wonders how the Doctor got the TARDIS into his room, if it doesn’t come apart, and asks him if they brought it in on a crane. If that’s the case, how did the Doctor get the rug underneath it? She asks many of the questions his other companions never thought of — such as how nothing can get through the TARDIS’ doors if they’re made of wood and have two windows in them, or why he has two hearts and whether that means he has high blood pressure, and the how and the why of how the sonic screwdriver works. The Doctor likes her, because of her almost constant interrogation and logic (she points out that it’s not exactly safe for her to be wandering around Victorian London. You know, black girl in a time of slavery and all?). Bill has a strong sense of Fe. She empathizes heavily with other people, becomes emotionally involved, and does not hesitate to interrogate the Doctor or pass silent moral judgments on his behavior as she reads between the lines and senses the truth behind his words (she asks him how many people he has killed, after seeing his lack of concern at a death, and then asks him if he “lost count”). She is coolly confident in asserting herself as a lesbian, and in letting boys who crush on her down easily but firmly. Bill tends to make sharp moral judgments about people, especially Missy (“She’s a murderer, and you let her out?”). When the Doctor wants to sacrifice himself, and spend eternity fighting in a void, she slams him with objective thinking – this is not his job, the universe needs him more, and he has a vault to guard, so he’s not doing it. When the Doctor tries to mind wipe her, she objects at first but then agrees, with the proviso that he think how he “might feel, if someone did this to you.”

Enneagram: 7w6 so/sp

Bill is a wisecracking, funny, and excitable companion who just wants to have a good time. She is eager and excited to go on adventures on different planets. Like many of his former companions, she becomes more and more excited to engage with other worlds, the creatures and the people in them. She’s highly logical, but also sees the humor in most situations. Her brain works at a million miles per hour and sometimes the Doctor struggles to keep up with her thought-tangents (7-core Ne-doms have the “busiest” but most scattered thinking). Her 6 wing is playful, helpful, and cautious about the unknown, sensible enough to realize when things are dangerous and want to avoid making anyone angry with them. Under stress, she can disintegrate into 1 and become more moralizing. She urges the Doctor to become more chivalrous and to care about people’s welfare. Even when she is angry with him, she chooses to do the right thing and help him save others.