Ilsa Faust is a major character in the Mission Impossible film series, serving as one of the two deuteragonists (alongside Benji Dunn) of the 2015 film, Mission Impossible: Rogue Nation, one of the three deuteragonists (alongside Dunn and Luther Stickell) of its 2018 sequel, Mission Impossible: Fallout, a major character in the 2023 film, Mission Impossible: Dead Reckoning Part 1, and a posthumous protagonist in the upcoming 2025 film, Mission Impossible: Dead Reckoning Part 2.
Ilsa is a former intelligence operative employed by MI6 who worked for an international terrorist organization called The Syndicate as a cover assassin before helping Ethan Hunt and his IMF team to fight her former colleagues.