|Eren. You couldn't save your mother because you lacked the strength. And I...I couldn't stand up to the Titan because I lacked the courage!|
|— Hannes to Eren|
Hannes was a tall, well-built man with short blond hair, a thin dark mustache, and golden hazel eyes. He wore the typical uniform of the Garrison Regiment along with a gray v-neck shirt underneath.
Hannes was a very kind, good-natured man, but he often drank irresponsibly. He was greatly ashamed of his lack of courage five years ago, and cared deeply for Eren and Mikasa. He looked out for them after Carla was eaten. Five years after the fall of Wall Maria he became a more dutiful soldier and more serious about the Titans.
When Keith Sadies found a civilian beyond Wall Maria, the man was imprisoned for leaving the Walls without permission, and Hannes was stationed at his jail cell to watch him. Drunk while on duty, Hannes was perplexed that anyone besides the Scout Regiment would be "stupid" enough to leave the Walls, suggesting instead that the man may have left the Walls while intoxicated, explaining his memory loss.
The man, Grisha Jaeger, soon began working as a doctor in Shiganshina District. When a plague broke out in the district, Hannes' wife was among the afflicted who were saved when Grisha developed a cure; a debt to the Jaegers he became determined to repay.
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 help Eren with Armin Arlelt trailing behind. The soldiers then cheered on the children as they fought until the merchant threw a bottle at Hugo, calling him a waste of taxes. While Hugo attempted to fight him, Hannes claimed that the merchant was speaking the truth and stopped him until the merchant hit him in the face as well. The two then engaged in a fist fight until a Military Police officer came and stopped them, causing the three boys and Eren to run off.
While on duty, Hannes and his companions keep themselves entertained by drinking and playing card games. Their fun is interrupted by Eren Jaeger, who criticizes them for not taking their job seriously and demands to know what they would do if Wall Maria was breached by the Titans while they were drunk. Hannes in unconcerned with Eren's complaints, assuring him that the Walls, having stood strong for over a century, will never be breached. When this does nothing to calm Eren down, Hannes argues that he should be happy that the Garrison has nothing to do, as the day that they have their work cut out for them will be the day that Titans really do break in and threaten the peace of the Walls. Eren finishes the conversation by arguing that living inside the Walls their entire lives makes them no more than caged animals, and as he leaves, Hannes begins to worry that the boy wants to join the Scout Regiment.
During the fall of Shiganshina and subsequent Titan invasion, Hannes is informed in the midst of the chaos by Armin Arlelt that Eren and Mikasa Ackermann went to their house to see if it has been destroyed, and may be in danger. Going to their house, Hannes arrives to find them desperately trying to free Eren's mother Carla, who has been trapped underneath the rubble of the house. Carla begs him to take the children and run, but Hannes assures her that he will slay the approaching Titan and rescue all three of them. However, as he prepares to attack the Titan, he finds himself frozen in fear at the sight of it. Unable to bring himself to fight the Titan, Hannes grabs Eren and Mikasa and flees, leaving Carla behind.
After they have escaped, Eren begins punching Hannes repeatedly, insisting that he would have been able to save his mother if Hannes had given him more time. Hannes throws him to the ground, telling Eren that he would not have been able to save his mother as he was not strong enough. Enraged, Eren continues punching, but Hannes catches the boy's punch, tearfully explaining that he himself had not been able to save Carla because he lacked the courage to try. He escorts the two away from the chaos, apologizing repeatedly.
After escorting Eren and Mikasa to the boat carrying refugees out of the district, Hannes participates in the evacuation of Shiganshina. He tries to reason with the other Garrison members, saying that if they close the gate the people inside the district 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. Managing to escape the impact, Hannes retreats to the top of a nearby building and watches in horror as Titans pour through the destroyed gate into Wall Maria.
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, Hannes' squad takes up positions atop Wall Rose to serve as lookouts, in case the Colossal Titan returns. As Hannes admires the harpoons that were set up to catch any Titans near the wall, his subordinate Phil expresses his fear for their comrades, reminding Hannes that Eren, Armin, and Mikasa are members of the vanguard. Hannes calmly tells Phil that he is sure all three are still alive.
As Hannes works on the cannons mounted on the Walls and sees Eren walking with Commander Pyxis. Seeing this, he feels relief that Eren is okay and survived fighting inside Trost. Eren signals to him to focus on his work, annoying Hannes that Eren would dare talk to a superior officer that way. Hannes deduces from Eren's demeanor that Mikasa and Armin are also alright, and begins to wonder why Eren is walking with the commander as they leave.
Hannes appears once more apparently giving a report to Dot Pyxis when a Garrison member bursts in and informs them that Wall Rose has been breached. Hannes' unit is assigned to patrol Wall Rose to find the breach. As they patrol, Hannes is bewildered by the fact that they have yet to encounter any Titans, noting that all previous breaches have only occurred after a large amount of Titans have been gathered together at the source of the breach.
Hannes' unit searches through the night, but does not find any breach in the wall. They double back, and meet up with Scouts to relay their findings. As the Scouts depart, Hannes advises Eren, Armin, and Mikasa to keep their guards up, before departing with his unit as well.
Hannes is almost immediately drawn back to the Wall by the appearance of the Colossal Titan. Although he is shocked to see it again, he is more concerned with finding Eren and making sure that he is safe. Historia Reiss points him to where Eren is engaged with the Armored Titan. Just as Hannes gets his first glimpse of Eren's Titan form, the Colossal Titan pushes itself off the side of Wall Rose, allowing itself to fall on top of Eren and the Armored Titan. In the resulting explosion, the two enemy Titans are able to escape with Eren.
In the aftermath, Hannes is one of the few commanding officers left unharmed by the impact of the Colossal Titan's fall. Once Mikasa and Armin wake up, Hannes brings them food rations, and sits down with them to eat. He tries to lighten the mood by bringing up the fact that the two are still having to fix situations caused by Eren. He fondly remembers the way that Eren would constantly throw himself into fights and never admit defeat to anyone, pointing out that all Eren really has to do at the moment is slow down the two boys who kidnapped him until they can go to rescue him. He rounds out his speech by informing Mikasa and Armin that he will be joining the mission to rescue Eren, as he feels that he will never be able to go back to the peaceful days he enjoyed in Shiganshina if Eren is not recovered.
When they arrive at the Titan Forest, Hannes commands Phil to watch their horses as he enters the forest, and orders the rest of his unit to search for the enemy and report back if they find them. Although they find the traitors in the forest, they are not able to catch them. As their enemy flees out of the forest, Hannes orders his unit to continue their pursuit on horseback. He swears that he will rescue Eren, even if it costs him his life.
Catching up to the Armored Titan, Hannes joins the rest of the soldiers in attempting to attack it, to no avail. He falls back as the 104th graduates attempt to reason with their former comrades, but orders them to fall back as well when he see Erwin leading a horde of Titans directly towards Reiner. As the Armored Titan attempts to force its way through the Titan horde, Hannes joins the rest of the soldiers in a full-scale attack on it.
Erwin finally manages to take back Eren, and the military forces begin to retreat. However, their path is blocked by the Armored Titan, who begins throwing Titans to block the escape route. Eren and Mikasa are knocked off of their horse, and Hannes is forced to intervene to save them from a nearby Titan. Recognizing the Titan to be the same one that devoured Carla, Hannes is thrilled at the chance to avenge her death. He engages the Titan in battle, and after a while, is caught. Neither Eren nor Mikasa can do anything to stop it, and Hannes' entire lower half is severed, tearing his spinal cord, killing him.
In the aftermath of the battle, Eren, Mikasa, and Armin grieve his death while they recall their childhood spent with him.
The night before the mission to retake Wall Maria, Eren, Armin, and Mikasa mistake an old Garrison soldier for Hannes, which makes them think about the past.
- Carla Jaeger - For unknown reasons, he owed Carla a debt. While Carla is trapped, he tries to make good on the debt by attempting to save both her and her family; Carla pleaded with him to save her family instead. He attempted to slay the Smiling Titan but lacked the courage. When Hannes grabbed Eren and Mikasa and decided to run, Carla thanked him for doing the right thing. He still felt guilty about leaving her. Years later, he made good on the debt by saving Eren's life by engaging the Smiling Titan, and died in the process.
- Eren Jaeger - Although fired up, stubborn, and persistent when Hannes abandoned Carla, Eren did not resent Hannes for not saving his mother. Eren shared memories of more peaceful times with Hannes and wished he could go back to those times.
- Mikasa Ackermann - He admired her toughness and referred to as the best fighter he ever saw. He saved her life along with Eren's on two occasions. He also shared memories of more peaceful times with her.
- Armin Arlelt - He admired his intelligence and referred to Armin as extremely intelligent. He also shared memories of more peaceful times with him.