Disciple of the Lich: Or How I Was Cursed by the Gods and Dropped Into the Abyss! (Light Novel)

An isekai adventure about an ordinary boy taken under the wing of a mysterious undead girl!

Official English-language publication of the Japanese light novel (ranobe):

不死者の弟子 ~邪神の不興を買って奈落に落とされた俺の英雄譚~ | Fushisha no Deshi ～Jashin no Fukyō wo Katte Naraku ni Otosareta Ore no Eiyūtan～