Hammer with his brother Sickle called were born as conjoined twins. Their father left them at circus, where they rised as brusiers. Joker and Harley Quinn wanted them in their own gang. However, he wanted them separated, sho Joker hired Dr. Tohams Elliot to perform the operation. After operation Joker keep Mr. Hammer and left Sickle at the Iceberg Lounge as a gift for the Penguin.