Eridahn Oersted is a college student in an unknown university who joined the subversive organization known as the Laniakea. When he successfully convinced the leaders to let him join them, they provided him a sniper rifle.
His Above and Beyond counterpart is Eliza Oersted.
At some point in 2018, Eridahn Oersted enrolled in Philippine Science High School's Main Campus.
Eridahn is seen talking to Sachikayla and Tyriann during a field trip, and even though the former finds him annoying, they discover he is an incredibly accurate shot, so they attempt to recruit him into their syndicate, which would later be known as the Laniakea. He is given a sniper rifle.
He uses it during several training sessions as part of his recruitment, and even uses his skill to help the other members with aim training.
Eridahn attends the batch's Graduation Ball after he graduates high school. During the ball, he loses his memory due to the cataclysmic result of Sachikayla and Tyriann's falling out.
To be added
Eridahn is calm, focused, and compassionate, making sure that he doesn't accidentally hog the spotlight all for himself. He is extremely loyal to the Laniakea primarily due to the L.E.N.S.es affecting his mind, though the incident at the Graduation Ball has changed that momentarily.