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 over-coat.
Marlene participates in the Survey Corps' mission to retake Wall Maria, and after the emergence of the Beast Titan and his forces, Marlene's squad is ordered by Erwin to regroup with Squads Dirk and Klaus to guard the Corps' horses. She and her fellow soldiers fight off nearby Titans to protect the recruits in Squad Dirk while they move the Corps' horse to a safe place. During the fighting, however, Marlene and her squad are killed by the Beast Titan, who starts throwing crushed boulders at them, cutting them all to pieces.