Illumi Zoldyck is a prominent character in the anime series Hunter x Hunter. As the eldest child of the notorious Zoldyck Family of assassins, Illumi is a master manipulator and expert in covert operations. His skills in assassination are unmatched, and he possesses a cold, emotionless demeanor. Illumi is fiercely loyal to his family, particularly his younger brother Killua, whom he is determined to control and guide into becoming the perfect assassin. His presence in the series often brings tension and complexity to Killua's character development.