Satana Hellstrom was born to a mortal woman, but his father was Satan!* Y'see, Satan had concocted a ridiculously-elaborate plan that involved coming to Earth, seducing and marrying a mortal woman, and then having two kids, Daimon and his sister Satana. Eventually, Satan was revealed, their mom went insane, and the family was split up. Satana went to live with her dad in a pocket dimension, embracing her father's evil ways. She was trained how to use her mystical birthright powers, and was bonded to a powerful demon called the Basilisk to increase her own powers.
Eventually banished to Earth, Satana stalked the streets as a succubus, draining men's souls with a kiss. While on Earth, she was tested by her father for loyalty, and rejected him. Satana now lives on Earth, looking for purpose while scheming to conquer Hell.
*Not the real Satan, but a lying yet powerful demon