AU thing where Owain (Adonis) ended up in Remnant, on the run with his child from some really bad wizards for book spoiler reasons. After getting stuck there, he decides to make the most of the situation and raise his kid in Remnant.
Beacon Academy: Professor Owain Tyto - Dust Sciences
Semblance: ??? - He has convinced everyone that he had a semblance that lets him see the composition of dust at super high magnification and clarity. In actuality this is just a natural thing all humans from his world do; he's a literal wizard.
A strict yet effective teacher who tailors his teaching for every student. Comes off as aloof but he really does care about his friends and colleagues.
He recently became a teacher at Beacon because his kid, Shea really wants to hang out with other kids. Though Shea is about 13-ish, they insist on going to a huntsman Academy to prove that they can look after themselves. So Owain was like "Ok, I suppose it would be good if you made friends."
Secret: He arrived in Remnant some hundred years (lifespans of Magusian humans are crazy long) before the main storyline. He and Ozma are long time friends. He is the oldest surviving member of Ozma's inner circle.
Thanks to him, technology has greatly advanced to the point where Dust is harnessed so effectively that it's almost like the good ol days when magic was a common thing. Owain may have had a hand in this by teaching and influencing many scientists over the years in secret but he won't admit it.
The Grimm threat is greatly reduced but ever present. He may or may not be the reason why Salem is trapped in ice.
Still, there Salem's presence is felt through her doomsday cult and they are the main threat of the story. They intend on someday freeing their queen and using the Grimm pools to continue her experiments. There is also a really big Grimm that has been kept hidden over millennia - Salem's masterpiece.
Owain has been researching the Grimm pools in secret to figure out how to kill Salem. He might have been infected by the pools (hence him covering one of his arms with his cloak).
He prefers to lay low and stay in the background (despite what his outfit might have you think). He can't let people know he has otherworldly magic since it'd cause people to panic. Ozma is the only one who knows.