|Defend him! Even if it costs us our lives...we must let Eren reach the gate!|
|— Ian to his comrades|
Ian was a tall man, with a fairly muscular build. He had gold eyes and straight, dark blond hair parted down the middle and tucked behind his ears, reaching the lower back of his neck. Ian had a notably slim face with defined cheekbones. He had only been seen wearing the Garrison uniform, pairing it with a tan shirt underneath.
Ian was usually strict and brief, but when in less-tense situations, would engage in conversation with the soldiers he worked with. He also had good faith in his allies and was obedient to his superiors. He usually would strategize plans with his comrades in a candor manner and was noted to have a good knowledge of alcohol by his Commander, Dot Pyxis. This however did not stop him from shouting orders to soldiers in desperate situations and thinking logically. Even when faced with the negativity of Rico and Mitabi, he chose to continue the operation to retake Trost District the way he thought was best, rather than retreating.
Ian first appears after Trost District is breached by the Colossal Titan. He orders Mikasa Ackermann to support the rear guard but she protests that she will only slow them down. Ian retorts that he did not ask for her opinion and says she should just obey.
During the evacuation, his team follows and tries to intercept an abnormal Titan as it targets evacuating civilians. Mikasa is able to catch the Titan and slay it before it kills anyone, and Ian commends her for her efforts. He is impressed by Mikasa's professionalism, as she apologizes for damaging her blades during attack, though he is unnerved by her utter calmness in the face of a life and death situation. The team continues fighting off Titans until they receive the signal to evacuate. Ian orders his team to climb the wall and provide cover for the advance team as they also withdraw, but Mikasa disobeys his orders and leaves, despite his protests.
After a rampaging Titan is revealed to be a cadet, Ian is among the Garrison soldiers who surround him and his allies as Kitz Woermann questions the cadet about the nature of his Titan transformation. Mikasa is one of the two soldiers who take Eren's side, and Ian vouches for her skill, explaining to Kitz that losing her would be a great loss to human forces. Kitz ignores Ian's advice and tries to execute Eren and his comrades, but he is stopped by the interference of commander Dot Pyxis.
A plan for Eren to use his Titan powers to seal the breach with a boulder is formed, and Pyxis places Ian, Rico Brzenska, and Mitabi Jarnach in charge of the elite squad assigned to protect Eren on his mission. Ian is given overall command of the squad, and despite his protests, Rico and Mitabi agree with the assignment. As they prepare to depart, Ian adds Mikasa to the elite squad, believing she will be useful.
The operation goes sour immediately, with Eren losing control of his Titan form and attacking Mikasa before eventually collapsing. As Titans begin approaching, Rico and Mitabi advise Ian to abort the mission and retreat. However, Ian orders them to take their teams and protect Eren until he can recover. Rico tries to argue that enough soldiers have already died for Eren's sake, and Ian loses his temper, demanding that Rico tell him any other way to take back Trost without Eren. Rico is unable to give an answer, and she and Mitabi are forced to go along with Ian's plan.
As the soldiers fight, they are gradually overwhelmed as more Titans continue to pour into Trost. As Ian is about to order a retreat, Eren finally awakens and begins to carry the boulder to place in front of Trost's gate. Ian orders his team to protect Eren at any cost, and orders Mikasa and Armin Arlelt to stay near Eren to defend him. He then notices that Mitabi's team, with no buildings to utilize their ODM gear, are approaching the Titans on foot to get their attention away from Eren. Realizing that there is no other way, Ian orders his team to do the same. Ian uses himself as bait to lure Titans away from Eren, and sacrifices his life in order to ensure the success of the mission. He dies after pulling a squad member out of a Titan's mouth, getting eaten in the rescued soldier's stead.
After Ian's death, Armin remembers him and Pyxis for having enough resolve to sacrifice what matters most, and abandon their humanity to ensure success.
He was a highly capable soldier, and his leadership skills were trusted enough to earn him command of the Trost mission.