Midori has grown up suppressing a lot.
His older sibling often overshadowed him in all aspects of academic achievement. Midori's few figure skating trophies are worth next to nothing in his traditional Asian family (who, of course, only care about grades) compared to his brother's many academic awards. He was often criticized for spending too much time in front of the computer, wasting time watching anime, going out with his (few) friends far too often.
His family was very disappointed to learn he was rejected from an internationally-ranked university, the one which his brother is currently attending. He chooses a high-ranked national school instead, both to please his family and because it would require him to move across the country for his studies. Any time away from his brother and parents is greatly appreciated in his eyes.
Midori suppressed his feelings of resentment and jealousy, shaping into the calm and stoic character that defines him. He also hid his love of anime due to being bullied in high school and taunted for being a "weeb"; he had few close friends that shared the same interests.
He shaped his personality through high school to be well liked, but yet mysterious and distant from the majority of people.
He continues to hide his interests to the world in university, shown as he hides the majority of his anime/gaming merchandise in the closet on his side of the room... Cian has always been curious but is far too nice to invade his roommate's privacy.
Midori connects well with Lila. However she has never been an "ideal" match in his eyes, based on her appearance. He seems to have developed a crush on Weiss however, though she only regards him as one of her two best friends.