Doctor Fate by J.M. Dematteis

Kent Nelson, the first Doctor Fate, has died, and not one but two people have stepped in to take his place! Chosen by the Lords of Order come Eric and Linda Strauss, who find themselves able to combine into a singular mystical force - the new Doctor Fate! Guided by the Lord of Order, Nabu, Eric and Linda face their own sets of complicated challenges, both mystical and otherwise, as they navigate the strange new circumstances in which they've found themselves in this series by legendary writer JM DeMatteis and Keith Giffen.