Oh wears his emotions on his skin like a living mood ring.
Oh is a Boov who believes in the Boov way... but the Boov way is not working for him. He is smart and hard-working, but is just enough of an individual that nobody really likes him. He knows this, and is desperate to belong, but this desperation only makes him try harder and thus stand out even more as an individual, which makes other Boov like him even less. He is funny—or wants to be—but since the Boov don’t really have a sense of humor, his jokes fall flat. Oh doesn’t know it at the beginning of the movie, but eventually comes to understand that he’s really more of a human being stuck inside the body of a Boov. And that is his journey.