Marlene was a woman of average height and build, and had shoulder-length blonde hair with bright eyes. When not wearing the Survey Corps' typical uniform, her attire consisted of a white button-up shirt, dark pants, and an overcoat.
Marlene participates in the Survey Corps' mission to retake Wall Maria, and after the emergence of the Beast Titan and its forces, Marlene's team is ordered by Erwin to regroup with Dirk and Klaus' teams to guard the Corps' horses. She and her fellow soldiers fight off nearby Titans to protect the recruits in Dirk's team while they move the Corps' horses to a safe place. During the fighting, however, Marlene and her team are killed by the Beast Titan, which starts throwing crushed boulders at them, ripping them all to pieces.