Marcel (マルセル Maruseru?) was the comrade and childhood friend of Reiner Braun, Bertholdt Hoover, and Annie Leonhart. He was part of the group sent to attack the Walls in year 845, but his mission was cut short by the sudden appearance of Ymir in her Pure Titan form.
Marcel had short brown hair swept back and an upturned nose. On the mission to breach Wall Maria, he dressed in a long jacket with a backpack likely filled with supplies for the long journey away from their hometown.
Marcel is only ever briefly seen in a flashback, but it is revealed that he saved Reiner from being eaten alive by a Titan by sacrificing his own life and dying in his place. This demonstrated Marcel's extreme bravery and his devotion to his friends. Despite his bravery, he did appear to show great fear in his last moments of life.
At some point in their journey, they set up an outpost. During their preparations, a Titan, later known to be Ymir's Pure Titan form, erupted out of the ground and surprised all of them, reaching for Reiner. Before it could grab him, Marcel pushed him out of the way in the last second, causing the Titan to instead grab him. While his friends watched in horror and ran away, he was eaten alive by Ymir, causing her to revert back to a human after the children were gone.
When a group of Titans are attacking a tower in Utgard Castle, Reiner remembers the time he was about to be eaten by a Titan, in which Marcel pushed him out of the way, leaving Reiner and Bertholdt to witness the death of their friend as the Titan devoured Marcel in front of them.
The following morning, with no weapons and their superiors all dead, the rookies prepare for the end. However, Ymir reveals her secret and transforms into a Titan, in order to fight off the horde of Titans from killing the others. Reiner and Bertholdt were shocked when they realized that Ymir is the same Titan that attacked them years earlier and is responsible for the death of Marcel.
Later, in the Forest of Giant Trees, Bertholdt expresses concern over whether they can trust Ymir and reminds Reiner of Marcel's death at her hands. He later questions Ymir about it, and she states that she does not remember doing it. Bertholdt accepts her apology and states that she probably did not mean to eat anyone in the first place.