Chosen for a secret experiment, the Army imbued him with a drug that allowed him to utilize and use up to 90% of his brain's capacity granting him enhanced physical powers and near-mastery control of his body (accelerated healing-factor and heightened senses) in an attempt to create metahuman super-soldiers for the U.S. military. Deathstroke became a mercenary soon after the experiment when he defied orders and rescued his friend Wintergreen, who had been sent on a suicide mission by a commanding officer with a grudge. However, Slade kept this career secret from his family, even though his wife was an expert military combat instructor.