What is "sylar"

Gabriel Gray, more commonly known by his pseudonym Sylar, is a fictional character and a primary antagonist of the NBC drama Heroes. Portrayed by Zachary Quinto, he is a superpowered serial killer who targets other superhumans in order to steal their powers. He served as the primary villain of the first season and then as a recurring antagonist. Over the course of seasons two, three and four, the writers depicted Sylar attempting at various times and under different circumstances to become a hero or curb his desire to kill, undergoing relapses at various stages. In the series' penultimate episode he experienced over three years of penitence within a mental prison, and later identifies himself as a hero in what became the show's series finale due to cancellation.

TV Guide included him in their 2013 list of The 60 Nastiest Villains of All Time.