A literary alter ego is a character created by an author to represent themselves in a work of literature. The crossword solutions for this term are Hyde (4 letters), MRHYD (5 letters), and MRHYDE (6 letters). Hyde is the most common solution, referring to Dr. Jekyll and Mr. Hyde, a novella by Robert Louis Stevenson in which the protagonist, Dr. Jekyll, creates a potion that transforms him into his evil alter ego, Mr. Hyde. MRHYD and MRHYDE are variations of this name, likely referring to the same character.