Regulus became a Death Eater in his youth, however, he became disillusioned with Death Eater philosophy after witnessing Lord Voldemort's method of achieving his aims, and defected to the Order of the Phoenix; becoming a double agent, working closely with his best friend and Order spy, Evan Rosier. Thanks to his skill in Occlumency, Regulus was able to, with tremendous difficulty, keep his true allegiance a secret from Voldemort. During this time, Regulus fathered a child, Dean, with his Muggle wife, Jennifer. As the war heated up, Regulus abandoned them in order to keep them safe, lest the Death Eaters find out about them.