Along with his flustered appearance, Hannes wears an orange jumpsuit and sports with a mop of blond hair. He also has a light mustache, and light brown eyes.
Hannes is usually in a drunk state but is a very concerned person for his school and acquaintances.
Hannes is the referee of the dodgeball match the school holds. One time in the game, he gets hit by the ball thus knocking him out.
Passing by Rico Brzenska and the group she is training, Hannes offers some help to a worn out Eren by giving him a demonstration of how to properly use the omni-directional mobility gear. Not knowing about the gear's damaged state, he proceeds to fly. Unfortunately, the gear busts and he collides with Jean. As he gains back to himself, Hannes confronts Eren convincing him not to give up and that he failed because he is drunk.
During the test results day, Hannes is cleaning the hallway when he is suddenly interrupted by a commotion coming from class 1-4.
During the school's 104th festival, Hannes stands in the line for Eren's cheeseburgers stand.
When Eren and the others venture into Titans' building and are chased by a group of Titans, Hannes appears from inside his office, a hole in the wall, and ushers them in. They find Rico and Ian have brought the Wall Cleanup Club's gear with them. After putting on their gear, Hannes tells them that he will get the Titans' attention while they move forward. He heads out wearing the gear, but accidentally crashes into a window, breaking it and falling over. As Titans look over the window, the others use this chance to sneak out. Earlier, Hannes explained the layout and pointed the way to the principal's office, telling them that their chee-burgs may be in the door inside the office, though it needs a key.
- Eren Jaeger - At some point in the past, Hannes had saved Eren from the Colossal Titan after it stole Eren's lunch. Hannes is always willing to help and guide Eren. Despite failing most of the time, he aims for Eren to think higher of him.
- Mikasa Ackermann - At some point in the past, Hannes had saved Mikasa and Eren from the Colossal Titan after it stole Eren's lunch.
- Rico Brzenska - As the advisor of her club, Hannes appears to be on good terms with Rico, though that does not stop Rico from pointing the blame for her broken gear on a clueless Hannes.