SEOUL—For decades, theme parks were built around beloved characters. Now, a Seoul-based startup wants to make the fan the star.

Millennials Works, which operates AI-powered immersive entertainment venues under its SPACE:V brand, announced Tuesday the launch of its Series A funding round—a milestone that arrives on the heels of a strategic investment from SM Culture Partners, the corporate venture arm of K-pop powerhouse SM Entertainment. Earlier backers Pacemakers and CNTTech also participated in the round, the company said.