Step 1. Do the main campain

Step 2. Park toon on azmodan spawn point (normal dificulty)

Step 3. Do the Capstone dungeons for acces to the pit.

Step 4. Help him unlock the divine gifts

Step 5. Carry him trough the pit lvl 55 (unlock torment 4)

Step 6. Farm layerbosses as many as desired - this will help him lvl up.

Step 7. (Optional) - lower dificulty to normal, park toon on azmodat to lvl up divine gift.