"Rebirth of the Undead King" is an american light novel written by Kevin Butman a.k.a Ink Bamboo. It began serialization during 2018 through the online platform Web Novel, but was later adapted to Light Novel format for future releases.
Rebirth of the Undead King follows the story of two protagonists: Zaros, an orphaned village boy, & Amro, a fallen death god banished and betrayed by his kin.
After a series of events that drive Zaros to the edge of death, the young man is saved by the earth-bound philactery of Amro. In order to do so, however, he agrees to pay the price of hosting the latter's soul in his body. In exchange, he is not only granted another chance at life, but also an opportunity to take revenge on those who slighted him and massacred his village.