Phasma is a human First Order captain, played by Gwendoline Christie in The Force Awakens (2015) and The Last Jedi (2017). She commands the First Order's stormtrooper programme, and she is instantly recognisable because of a costume decision — chromium armour — rather than anything she does on screen.
Parnassos
Delilah S. Dawson's Phasma (Del Rey, 2017) supplies the history the films never had time for, and it is not flattering. She comes from Parnassos, a world wrecked by a nuclear accident, where she led the warriors of the Scyre clan. When Brendol Hux crash-lands there, she sees the exit, betrays her brother Keldo, and leaves with the Imperials.
Loyalty as a tactic
The novel's thesis is that Phasma has no ideology whatsoever. She is not a fascist; she is a survivor who noticed that the First Order was the strongest thing in the room. She later murders Brendol Hux — the man who brought her out — in concert with his son, and systematically eliminates anyone who knows where she came from. Everything she does is a calculation about who can still hurt her.
The screen problem
On film she does almost nothing. She is captured, made to lower Starkiller Base's shields at gunpoint, and dropped down a garbage chute; in The Last Jedi she fights Finn on the Supremacy and falls into the burning wreck. The gap between how memorable the design is and how little the character is given to do became a running fandom complaint, and is the reason the tie-in novel and the 2017 Captain Phasma comic exist at all.
Finn
Her most important relationship is with a stormtrooper she trained and lost. FN-2187's defection is a failure of her programme, and the films use her as the face of the institution that took children and made soldiers of them. She is the manager of the First Order's original sin.
Reading her honestly
Phasma is a good character in prose and a poorly served one in film, and it is worth being straight about that rather than pretending the two versions are equivalent. Dawson's novel is a frame story told by a captured Resistance spy, which lets the book present her history as testimony rather than fact — an elegant way of writing a biography of someone who erases her own past.
Where to read her
Phasma first. The Captain Phasma four-issue Marvel miniseries (2017), which fills the gap between the two films, second.
