At Pop Mart’s shop in Hong Kong’s bustling Causeway Bay shopping district, a display of the toymaker’s newly launched character, Merodi, drew little attention on Friday morning. “A few people are buying it,” a salesperson said. “It’s not very well known yet.” The new series, Merodi After School, features a mischievous little girl with the magical ability to talk to animals. It was created by Taiwanese artist Will Chen Wei-hua. The launch came two months after Pop Mart’s previous debut,...