In the television series "Legion," the character with multiple personality disorder is David Haller, who is also known by the alias Legion. The show is based on the Marvel Comics character of the same name. David Haller is the son of Charles Xavier (Professor X) and is portrayed as a powerful mutant with a vast array of psychic abilities, each associated with a different personality residing within him.
Throughout the series, David struggles to control and understand his various personalities, and each one possesses unique powers and characteristics. The show delves deep into the complexities of mental illness, reality, and identity. "Legion" is known for its visually stunning and surreal storytelling, exploring the blurred lines between what is real and what is a manifestation of David's unstable psyche.