| The subject of this article is anonymous.|
The name used is an alias, nickname or surname found in an official source, but the actual in-universe name of this person is unknown in this continuity.
| This article is incomplete.|
Please feel free to edit this article to add missing information and complete it.
Grandpa Arlert is an older man with thin hair and a slight hunch. He is usually seen wearing a light turtleneck.
Much like his grandson, Grandpa Arlert is a timid individual. Despite this, he tries to come off as tough and intimidating to visitors; this is especially after Armin told his grandfather he did not want any visitors.
After Armin was embarrassed in a dodgeball competition, Mr. Arlert was told by his grandson not to let anyone see him. During the next school year, Mr. Arlert heard the doorbell ring and several of Armin's classmates were there looking for him. Arlert tried to intimidate them into going away but one of them, Mikasa, eagerly looked forward to the thought of beating him; this caused Mr. Arlert to back down and allowed them inside.