Oruo has a light brown undercut and peculiarly imitates Levi's emotionless eyes. He also wears the standard male uniform of the school.
Oruo is talkative, and likes to brag. His tongue-biting mannerism is pretty exaggerated that it has been shown that he bites his tongue at least three times a day. Oruo is also a hardworking student who is very overconfident. He has a tendency to copy Levi's way of speaking.
Oruo is approached by first-years who want access to his club. He denies their entry and fights Eren while trying to close the door. He falls and bites his tongue in the process. He is tended to by his friends who, unlike Oruo, welcome them into their club.
After receiving his test results, Oruo is seen seemingly lamenting his bad test score. He starts to blame himself for letting his guard down in the test, claiming that he never studies but still always gets a perfect score. Gunther and Eld counter his claim and say that his mother brags to them about how her son stays up half the night cramming before each test, to Oruo's annoyance. He then tells everyone to reveal their test scores at the same time, and is subsequently punched by Petra when his score turns out to be the highest among them.
When Year 1 Scouts club members arrive late, the upperclassmen start chastising the group, with Oruo telling Eren to always wear his full school uniform. Following a challenge by Levi, Oruo participates in the school's Sports Day games. In the last game, shoulder wars, he teams up with Petra, Gunther, and Eld. He and his classmates later come and help their underclassmen clean the playfield.
After the upperclassmen plan the Scouts club's customary "Test of Courage" night event for new club members, Oruo dresses up as Beethoven and heads to the music room in preparation to scare them. When Eren's group enters, Oruo starts playing the piano and everyone throws music instruments at him. He later chases after them at the gym with his classmates. When a giant cannon suddenly appears and starts chasing after everyone, Levi, irritated by all the commotion, hits it and it falls on top of Oruo.
Following a student council scandal, an election for a new president is held. When Eren and Jean head to put their posters up, they are shocked to see that the whole board is filled with one poster; Oruo's.
Oruo tells them to give up putting their posters, since he had filled every board with his. They both then put up their posters on top of his, to Oruo's shock. When it is time for Oruo's final presidential speech on stage, Oruo grabs the microphone, and as he tries to speak, he bites his tongue and is taken off stage.
In the school's 104th festival, Oruo and his classmates are waiting in the long line of their underclassmen's cheeseburgers stand. Oruo starts complaining he waited too long, before Petra shoves his chee-burg in his mouth. Oruo is impressed by the flavors and starts talking fast, speculating how the burger was made, until biting his tongue.
When Eren asks his upperclassmen for assistance in retrieving his stolen chee-burgs from the Titans' building, Oruo chastises him for arguing with Levi's decision to remain on standby. He later watches Ilse Langnar's broadcast of Eren and the others venturing into the principal's office, and is relieved once Eren manages to retrieve a chee-burg.
- Petra Rall - Oruo typically tries to impress Petra by boasting, which actually repels her from thinking highly of him. He tends to imitate Levi around her as well, often making her feel uncomfortable. Even so, the two of them seem to have a close friendship.
- Levi - Oruo is slightly intimidated by Levi, giving him the more reason to copy his actions. They are often comically interacting as club members.