Shiro no Necromancer: Shiryou Ou e no Michi The White Necromancer: Road to the Spirit King

Synopsis

Toru Kuromine died at the unfortunate age of 15 due to an illness, only to find himself reincarnated in the world of the game he played from his hospital bed, War Records of Discard! As he aims to become a necromancer, he faces early trials and tribulations because of his newfound childhood and training. Will he reach his goal of becoming a necromancer? Or well he be set on another path...? (Source: Mangamo)