Eros is a member of the Eternals, a genetic offshoot of humanity, that left for deep space from Earth thousands of years ago and settled on Saturn's moon of Titan. Eros is the youngest son of A'lars (also known as Mentor) and Sui-San, and he grew up on Titan to be a fun-loving, carefree womanizer and adventurer in contrast to his brother Thanos, a power-hungry, nihilistic conqueror. Only when Thanos launched his first major attack on Titan did Eros begin to take life a bit more seriously.