What the Phoenix Force is, why Jean Grey keeps hosting it, and what Sadie Sink’s MCU debut sets up for Marvel’s ‘X-Men’ film. Sadie Sink’s Jean Grey spends Spider-Man: Brand New Day as a teenage telepath with a narrow, specific power set and a dead sister to avenge. The film does not name the Phoenix Force once. That is why the Phoenix Force keeps producing tragedies instead of victories. Whether the Phoenix Force shows up in that film or three films later, the pieces on the board are the pieces from 1980.