1st, after you create a Necro(short for Necromancer) have a Ronin "Blood Bond" with him and let the Necro enter a "Watch Tower". After this let 4 ronin enter the Necromancer's Thrown. Have the Ronin who "Blood Bonded" with the Necro to die. When the Ronin dies, the 4 Ronin inside the Necromancer's Thrown will become a Necromancer.