Tezuka could never completely abandon medicine. Although he never actively practiced, he became a licensed doctor later in life, and one of his most famous manga series stars the rogue genius doctor, Black Jack. But life as both a doctor and an in-demand (though underpaid) young artist was difficult. Tezuka struggled to meet deadlines and commitments. His family feared for his health and begged him to focus on medicine, but he had become too successful, and too passionate, to stop.