Golden Age
An expert plastic surgeon, Ekhart was first referenced in Detective Comics #66 as being the one person who could repair the damage Harvey Kent (later renamed Dent) incurred in an acid attack at the hands of Vincent “The Boss” Moroni. However, Ekhart had been visiting his brother in Germany when the Nazis rose to power, and had been put into a concentration camp. He eventually escaped, and successfully performed surgery on Kent, aiding his rehabilitation.
Bronze Age
Ekhart made his first actual comics appearance in Batman #328. He was approached by Maroni, who survived a battle with Dent (who had become Two-Face again after a freak accident) and was looking to go into hiding. Ekhart gave the mobster a new face and identity as “Anton Karoselle.” When Dent discovered the truth, he wanted Ekhart to do the same for him, but Ekhart warned Dent that his particular facial injuries would not permit plastic surgery a second time. Nevertheless, Dent insisted, forcing the doctor to perform facial reconstruction surgery at gunpoint while Dent was awake and without anesthetic. Dent had a new face and identity, but as Ekhart warned, it soon began to deteriorate. When Ekhart informed Dent that there was nothing more to be done, Dent murdered Ekhart in order to keep the doctor silent, and for aiding Maroni.