|Oruo! Petra! For a couple of soldiers who cried and pissed their pants during their first battle, you've really grown!|
|— Eld teases his teammates|
Eld had brown eyes and long blond hair which had a middle parting and a bun folded at the back to keep his hair tied. He also had a small beard. He had small brown eyes and a serious face. Like most other Scout Regiment members he wore a green cloak with The Wings of Freedom emblem on the back. He wore the same uniform as the other Scouts and had a white shirt underneath.
Eld was a responsible and firm leader with a strong sense of duty. He did not talk much, but when he did, he spoke bluntly and in a straightforward manner. He also seemed to have been a veteran of sorts as he teased Petra Rall and Oruo Bozad about having wet their pants on their first expedition, and sarcastically referred to them as "fine fearless soldiers." He also seemed to hold some sort of belief of what makes a true soldier, as he lectured Oruo that a kill record alone does not make a great soldier.
When Eren accidentally transformed, he seemed to have been more concerned about the reasoning as to why and demanded an answer from Eren. His reaction was interesting in comparison to his comrades; Oruo threatened to kill Eren, Petra feared for Levi's life, and Gunther demanded evidence from Eren about his transformation and intentions.
Along with the other members of the Special Operations Squad, he had some remorse over his reaction to Eren's transformation as he bit his hand just like Eren, which symbolized a bond between them.
Eld participates in the 49th expedition beyond the Walls. During the expedition, while the Scout Regiment is setting up a base, Eld is left in command of Oruo Bozad and Petra Rall, and scolds them when he finds them apparently slacking off on their duties.
When Hange Zoë breaks away from the regiment to pursue a Titan on her own, Erwin sends Levi's squad to keep her safe. They pursue the Titan to a clearing where it is killed, and subsequently discover the headless corpse of a soldier seemingly enshrined inside of a tree.
After the post-Trost District battle trial to decide Eren's fate concludes with Eren joining the Scout Regiment, the Special Operations Squad, is assigned to look after Eren. Eld, along with the rest of the squad, accompanies Eren to the former HQ of Scout Regiment, which will now serve as a hideout for Eren. After their arrival, Eld and Gunther notice that the HQ has not been properly maintained due to being unused. Due to that, Levi orders everyone to begin cleaning. Later that day, while the squad discusses the upcoming expedition, Hange arrives and Eren asks her to explain her experiments with Titans. Gunther and the rest quickly leave the room, already painfully familiar with Hange's long-winded speeches about Titans.
The next day, Eld, along with the rest of the soldiers, arrives to the crime scene after being notified about the killings of Sawney and Beane. After the investigation is done and the culprit is not found, Eld and Gunther discuss the upcoming induction ceremony, asking Eren whether any of his classmates will join, but Eren is unable to answer with certainty. Eld is then present at the said ceremony, listening to Erwin's speech.
Levi finds a way to contain Eren in his Titan form without killing him, allowing Hange to run experiments on him, which Eld and the rest of the squad monitor. Eren is unable to transform for some reason, but later triggers his transformation while attempting to pick up a teaspoon. Eld and the rest of his squad mates immediately prepare to kill Eren, believing he has betrayed them, but Levi keeps them at bay. Later, Hange reveals to everyone the secret behind Eren's transformation. Realizing their mistake, Eld and others bite their hands as a form of punishment, showing that they can trust each other.
One month later, Eld is part of the expedition that heads into the Titan territory. As time progresses, the news of a mysterious Titan killing the soldiers reaches the Levi Squad just as Eld and others witness the black smoke signal, knowing that an abnormal Titan is near their position. Eventually, they enter the forest. Eren questions this, but then notices Eld and others also do not know what is going on. At that moment, the mysterious Female Titan reaches their location. As they are being chased, Eld and the other squad soldiers beg Levi for orders, proposing to take the Titan down as it slaughters the reinforcements from behind. Levi, however, just shoots a sound grenade to calm them down, reminding them of their job. Eren finds himself to be unable to comply with the orders as he watches more soldiers to be killed. His intentions are made clear when he is about to bite his hand.
Levi tells him to choose whether he believes in himself or the squad. Eren decides to go with the squad, and as the Titan is about to catch up with them, they reach the location of Erwin and other soldiers who manage to trap the Female Titan, much to the surprise of Gunther and the squad. They then brag to Eren, claiming that it is thanks to the power of the Scout Regiment that they managed to capture their foe.
Afterward, Eld and others discuss Erwin's decision not to tell the soldiers about the plan. Eren wonders why is it that not even the elite soldiers were told about it, angering Oruo and Petra, but Eld agrees with Eren, stating that Erwin must have had a reason. They realize that if they answered Erwin's mysterious question back then, they would probably be trusted enough to be let in the operation.
Seeing a flare that indicates the regiment is retreating, the squad begins making their way out of the forest. On their way to rejoin with Levi, Eld teases Petra and Oruo for peeing their pants on the first expedition. They notice another signal flare and thinking it is shot by Levi, they fire their own one. However, the mysterious soldier kills Gunther and then transforms into the Female Titan to resume her pursuit of Eren.
Eren is ordered to flee while the surviving squad members engage the Titan in battle. The squad seems to have the upper hand, with Eld launching an attack and a smoke screen blinding the Titan that allows Petra and Oruo to take out her eyes. Eld then launches several attacks on her arms before Oruo and Petra joined in, severing them and rendering them useless. As Eld and Petra move in for the kill, the Titan suddenly regenerates a single eye and bites Eld in half, also severing his arm. Eld's upper half is thrown to the ground as the Female Titan engages Petra and Oruo, killing them both while Eren looks on in horror.
During the Battle of Shiganshina, as Erwin Smith begins to lament the dwindling hopes of his dream, Eld stands among the many fallen Scout Regiment comrades in Erwin's mind, wanting to know if their deaths had meaning.
Eld was a very adept warrior who had a very high kill record of 46 Titan kills (of which 32 were with a team and 14 were solo). He also seemed to have been very proficient with the omni-directional mobility gear, using fake-outs with the steel wires to propel himself backwards during an attack in combination with using the ODM gear to help him brake while simultaneously using the gas exhaustion as a smoke screen to blind a Titan and support his comrades' attack. He was very skillful when using his blades to bring down the Female Titan's arms, as shown by him using a variety of different attacks.