Seo Dal-mi is a fictional character from the South Korean television series "Start-Up." She is portrayed as a determined and ambitious young woman who dreams of becoming a successful entrepreneur in the tech industry. Her character embodies resilience and the pursuit of innovation, often facing challenges as she navigates the competitive world of start-ups. In the series, Seo Dal-mi is depicted as the younger sister of Seo In-jae, who has a contrasting personality and background. The storyline explores their sibling rivalry and personal growth, highlighting themes of ambition, love, and the complexities of family relationships in the context of the start-up culture.