Hoping this isn't entirely too long, and of course its just a base idea. (image is my own) Wafa (MC) is a necromancer who specializes in healing, using his powers and experience to help people. He dedicates his life to the healing arts, to studying necromancy and it's possible contributions to healing and so forth. Following through to the inevitable, he begins extensive research on full resurrection. Not just zombies, not just ghouls, not just patching someone up close to the edge, real, true, body, mind, spirit resurrection. Soon, it overtakes everything else, and he begins joining various wars to test his theories, to continue to give healing help. Soon, he even receives funding from captains and higher ups to excel in his resurrection research. Soon, he meets (YC) a soldier (this can be tweaked to your own likes) who is placed in the same outpost as Wafa, and made to work together through the area; an enemy torture facility. The souls within are constantly in agony, angered by their ends, constantly looking for something to latch onto, to grasp. Naturally, as someone who already works with spirits, Wafa makes for an excellent medium. He's soon possessed, though it isn't normal...it occurs over time, slowly affecting his moods, his health. Soon, his body can't take much more, and he dies. With (YC)'s help (MC) discovers the secrets of resurrection, and makes it back to the sentient world of the living. Returning to life is difficult and painful, reconstructing bones, muscle, sinew. He's not quite all there when he comes back, and needs help to lead a happy life, (A bit hurt/comforty, but this is a rough idea) and also keeping the secrets of resurrection just that, a secret.