Cain is a young English nobleman, known as the Earl or Count of Poison due to his passion for collecting and storing various poisons, which he affectionately refers to as his "children." His childhood was marred by both physical and mental abuse at the hands of his father, Alexis. Daily, Cain was whipped on his back because Alexis believed Cain was a cursed child and this was the only way to seek forgiveness from God. Cain's mother, Lenora, even attempted to kill him, as he was the illegitimate offspring of her husband Alexis and his sister Augusta. At the age of twelve, Cain became the Count after killing his father—an act that led to him being named after the biblical figure Cain, who was the first human to murder a relative, his brother Abel.
Cain possesses green-gold eyes, which appear green but have golden flecks due to his birth from an incestuous relationship. To the outside world, he presents himself as a wealthy, incorrigible playboy. The only individuals he truly trusts are his head butler Riff and Mary Weather, whom many believe to be his half-sister through Alexis' liaison with a maid. The manga drew inspiration for Cain's physical appearance from British actor Rupert Graves. So striking is Cain's beauty that he can easily pass for a woman.
