A Russian assassin in Anthony Horowitz's Alex Rider series. Not that we like to think of him as an antagonist *shrugs* He agrees with the main protagonist, Alex Rider, that he should live a normal life outside of the espionage world(which sadly never happened because the series is a spy thriller). He's hot with chiseled lips and a dancer's body. He's dead.
Person A: omg Yassen Gregorovich is so hot!
Person B: he's literally an assassin!