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 is seen attending a meeting with Erwin Smith and the rest of the Survey Corps' officers to discuss the recent revelations about Eren's father Grisha Yeager. As the officers leave the meeting, she teases Hange about her past infatuation with Keith Shadis.
Marlene then participates in the Survey Corps' mission to Shiganshina, 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.
- Hange Zoë - Marlene and Hange had a close relationship with each other, and were seemingly old acquaintances. She seemed to take pleasure from teasing Hange and giving her a hard time.
- During her appearances, Marlene's hair is drawn inconsistently, alternating between being parted down the middle, and having her bangs pulled back out of her eyes.