Grior (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.
Grior was a young man with dark hair, which was kept closely shaved. He had only been seen wearing waiter's clothes. After he was freed from the restaurant by Yeagerists, he wore a dark jacket and pants similar to the Anti-Marleyan Volunteers.
Grior seemed to be a very cold man, feeling no qualms about betraying Niccolo due to the latter's friendly attitude towards Eldians. He also seemed to be somewhat distrustful, believing that Niccolo's friendliness meant he had switched allegiances, and appeared unwilling to believe that the wine that had been distributed throughout Paradis was laced with Zeke's spinal fluid.
Grior 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 Niccolo.
When a group of officers from the Survey Corps come to visit Niccolo at his restaurant, Grior contacts the Yeagerists to inform them of the officers' location. After the group arrives, Grior helps them arrest the Corps officers. The officers try to warn them about the threat posed by Zeke's spinal fluid being distributed throughout the Walls, but Grior dismisses the threat as a mere theory dreamed up by Niccolo.
Grior comes with Onyankopon and Yelena in prison to see Niccolo and the other prisoners. When Niccolo 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 Niccolo for siding with the Eldians. Grior goes on to recall how Niccolo 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.