Greiz (グリーズ Gurīzu?) was a former Marleyan soldier who served on Marley's Navy and was part of a survey fleet sent to Paradis Island after the failed Paradis Island Operation. After being taken captive on the island, he began working as a waiter in a restaurant inside the Walls.
Greiz was a young man with grey hair, which was kept closely shaved. He had originally only been seen wearing waiter's clothes. After he was freed from the restaurant by Jaegerists, he wore a dark jacket and pants like the other Anti-Marleyan Volunteers.
Greiz is among the Marleyan soldiers who are dispatched as part of a fleet to survey Paradis Island, and is summarily captured by the Eldians living on the island. He is put to work as a waiter in a restaurant run by his fellow soldier Nicolo.
When a group of officers from the Scout Regiment come to visit Nicolo at his restaurant, Greiz tells Nicolo and contacts the Jaegerists to inform them of the officers' location. After the group arrives, Greiz helps them arrest the Scout officers. The officers try to warn them about the threat posed by Zeke's spinal fluid being distributed throughout the Walls, but Greiz dismisses the threat as a mere theory dreamed up by Nicolo.
Greiz comes with Onyankopon and Yelena in prison to see Nicolo and the other prisoners. When Nicolo wonders if they will become the new rulers of Paradis after the plan by Zeke and Eren is put into effect, he begins to insult Nicolo for siding with the Eldians. Greiz goes on to recall how Nicolo talked about Sasha every night and insults her legacy by calling her a whore and a filthy island devil; before he can say anything else, he is immediately shot in the head by Yelena.