|Eren... The reason you couldn't save your mother is that you lacked the strength. The reason... The reason I didn't fight the Titan was that I lacked the courage!|
|— Hannes to Eren|
Hannes is a tall, well-built man with short blond hair, a thin dark mustache, and golden hazel eyes. He wears the typical uniform of the Garrison Regiment along with a gray v-neck shirt underneath.
Hannes is a very kind, good-natured man, but he always drinks irresponsibly. He is greatly ashamed of his lack of courage five years ago, and cares deeply for Eren and Mikasa. He looked out for them after Carla was eaten.
Before the Fall of Wall Maria, Hannes would often sit around drinking and socializing with fellow soldiers in Shiganshina District. On one of these days, Eren Jaeger got into an aggressive fist fight with three other boys and the soldiers were called upon by a merchant to stop them. However, a drunken Hannes claimed that someone more qualified to help would be along shortly. Moments later, Mikasa Ackermann came to save Eren with Armin Arlelt trailing behind. The soldiers then cheer on the children as they fight until the merchant throws a bottle at Hugo, calling him a waste of taxes. While Hugo attempts to fight him, Hannes claims that the merchant is speaking the truth and stops him until the merchant hits him in the face as well. The two then engage in a fist fight until a Military Police officer comes and stops them, causing the three boys and Eren to run off.
Hannes is first introduced as being drunk while on duty, in the Shiganshina District shortly before Wall Maria fell. He and a fellow Garrison member, Hugo, are chided by Eren, who thinks they are being reckless by drinking as the Walls could fall any day. Hannes however is relaxed, saying that the Walls have stood for a century without a breach.
During the fall of Wall Maria and subsequent Titan invasion, Hannes arrives at the scene with Eren, Mikasa and Carla Jaeger as she is trapped underneath her house that was hit by the rubble caused by the Colossal Titan's attack. She begs him to take the children and run but he wishes to instead kill the approaching Titan and rescue Carla as well. Horrified by the distinct wide, grinning face of this Titan, Hannes saves Mikasa and Eren from certain death, despite the fact that he does not have the courage to fight the Titan that devours Carla.
Moments after the traumatizing event, Eren punches Hannes repeatedly, crying out why he could not save Carla, and Hannes throws him to the ground. Eren continues his blind efforts of attacking Hannes, with Hannes tearfully explaining that the reason Eren could not save his mother was because he lacked the strength, further infuriating Eren, but Hannes says that the reason he himself could not save Carla was because he lacked the courage. He escorts the two away from the chaos.
Hannes escorts Eren and Mikasa on the boat escaping the district and shortly after participates in the evacuation of Shiganshina. He tries to reason with the other Garrison members, saying that if they close the gate the people outside the Walls will be devoured, however the other argues that the Titans will invade the entirety of Wall Maria if they do not. Hannes attempts to stop the command, but the conflict is short-lived as an Armored Titan breaks through the Shiganshina gate, and Hannes watches in horror of the aftermath of the blow.
Hannes meets Eren, Mikasa, and Armin again five years later in Trost District and compliments them for graduating from the cadet corps, as Eren compliments him for earning the rank of Captain. After fooling around a bit, Hannes becomes serious and apologizes for not being able to save Eren's mother. However, Eren does not blame him for this, and claims that they will never let a tragedy like that happen again before running off. Hannes briefly thinks to himself, wondering if he should be happy that Eren has grown up. He then wishes for him not to die.
After Trost District is attacked by the Colossal Titan and breaks down, all the citizens are evacuated and the town is filled with Titans. During this time, Hannes works on the Cannons mounted on the Walls and sees Eren walking with Commander Pyxis. Seeing this, he feels releif that Eren is okay and survived fighting inside Trost. He then sees Eren signal to him to focus on his work, causing Hannes to question that he dare talk to a superior officer that way. However, Hannes deduces from Eren demeanor that Mikasa and Armin are also alright. He then begins to wonder why Eren is walking with the commander as they leave.
Hannes appears once more apparently giving a report to Pyxis when a Garrison member bursts in and informs them that Wall Rose has been breached. He is the commander of the Wall Rose counter squad and heads out to find the breach. Hannes is surprised to find no sign of a breach and in fact no Titans near the Wall itself. After relaying this information to Hange Zoë, who is equally surprised, he begins to leave.
Hannes is unable to leave because he becomes involved in the battle with the revealed Armored Titan and Colossal Titan. He expresses shock once he sees the Colossal Titan atop the wall and angrily wonders why it showed up there. He asks Historia about Eren and she points towards the other side of the wall. Hannes is surprised when he sees Eren's Titan form for the first time. After the Armored Titan roars, Hannes watches in shock as the Colossal Titan starts to fall off the wall.