Samuel Seo is introduced appearing sophisticated and more mature than his actual age. He has fair skin, with a strong V-Shaped jawline and dark, narrow eyes. His figure is extremely muscular, with a more prominent, broader chest and arms than a majority of characters. His black hair is combed back neatly, and he wears slender, rectangular glasses. He is revealed to bear tattoos, consisting of Sak Yant and images of various objects. He is very serious and disinterested