Moon Sang Tae is Moon Gang Tae's older brother, who is autistic. He is a fan of Moon Young, as well as an aspiring illustrator. He was the sole witness of his mother's murder, which resulted in his irrational fear of butterflies, as they reminded him of this traumatic experience. His fear develops into nightmares every spring, and forces Gang Tae to move towns with him in order to "run away from the butterflies".
(Source: Wikipedia)
