Mulligan has a warm, brown complexion and short, slightly messy brown hair. His most striking feature is his magenta irises which seem to shimmer like twilight. He keeps a neatly trimmed stubble and often wears colorful, flowing silks that seem to catch the light in impossible ways.

He is a creative spirit who views the world as an unfinished painting. A chronic jokester, Mulligan uses his wit to deflate tension and his magic to bring laughter to others. He is surprisingly humble despite his celestial heritage, preferring the title of 'Brother' or 'Friend' over anything grander.

Mulligan is the fifth child of the An clan, a noble family known for their rigid adherence to tradition and law. Born as the younger twin, he was always the shadow to his brother's bright ambition. His mother, a powerful land spirit of the dream-mists, bestowed upon him the ability to touch the minds of others and shape their sleep. While his siblings studied warfare and politics, Mulligan spent his years in the library, not for the books, but for the quietude where he could better manifest his internal fantasies. He became a Sage of the Ethereal, mapping the landscapes of human consciousness. He eventually left his ancestral home when his family tried to arrange a marriage of political convenience, realizing that his spirit could never be caged by earthly contracts. He travels now to prove that the boundaries between dreams and reality are thinner than most dare to believe.