Ian was a taller 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 cheek bones and light skin. 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. He later compliments Mikasa for killing a Titan that was running towards a group of evacuating civilians.
Ian next appears when Kitz Woermann is questioning Eren about the nature of his Titan transformation. He vouches for Mikasa's skill and explains that losing her would be a great loss to human forces. When the plan for Eren to use his Titan powers to seal the breach with a boulder was formed, Dot Pyxis places Ian in charge of the elite squad assigned to protect Eren on his mission.Once Eren lost control of his Titan form, Rico Brzenska advises Ian to abort the mission and retreat. However, Ian orders his soldiers to continue to defend Eren down to the last man, as Eren is their only hope against the Titans.
Eren regains his senses due to Armin Arlelt's intervention, and Ian, seeing the chance, orders his soldiers to protect him until he reaches the breach, even if it costs them their own lives. 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, in a manner similar to how Eren saved Armin, but is eaten when it pushes him into his mouth in such a way that his head is bitten off by it.
After Ian's death, Armin remembers him and Pixis for having enough resolve to sacrifice something to ensure success.
He was a highly capable soldier, and his leadership skills were trusted enough to earn him command of the Trost mission.