As the son of the chairman of the Star Group conglomerate, he possesses excellent looks, intelligence, and athletic ability. However, he suffers from over 200 allergies, atopy, and various other skin conditions. His physical strength is low and he is sensitive to stress, making his body overall very frail. To overcome this, he jogs daily and has consistently played basketball, showing that he manages his health to prevent it from worsening. Nevertheless, because his body is so weak, he gets dizzy if he overexerts himself and frequently visits the hospital. Furthermore, under strong stress or pressure, his condition can deteriorate rapidly. While the exact name of his illness is unknown, when such situations occur, his body stiffens, he collapses, and he exhibits symptoms like high fever and red spots; in severe cases, he may even need to change his environment entirely. In addition to his allergies, low stamina, and sensitive body, he has congenital allergic asthma. If the environment worsens due to fine dust or air pollution, his symptoms become so severe that he cannot survive without medication. He also suffers from nausea and severe vomiting as a side effect of his medicine. Despite his weak health, he is a handsome chaebol heir with incredible specs, boasting a dedicated fan club. He is a celebrity-level popular figure, receiving immense support and love from the girls who make up a large portion of the audience at every competition. His only flaw, if any, is his extremely cold and prickly exterior. However, he serves as the leader and pillar of the Saebyeok Elementary Experiment Club, thanks to his vast scientific knowledge and the skills he has built through extensive experimental experience and formal academy training since childhood. In competitions, Won-so and Guest are usually the ones who handle topic selection, planning, and execution. When Won-so was young, he was experimenting with his childhood friends Sena and Heo Hong. During the experiment, sodium hydroxide—a strong alkaline solution that causes severe burns on contact—was spilled on his beloved prairie dog, Sol, resulting in Sol's death. He considers this a major trauma. To this day, he still finds things like animal testing difficult to handle.