The Trihexa King's Rebirth

The Trihexa King's Rebirth (Trihexa no ō no fukkatsu;の王の復活)is a story about Yusei Satan-Lucifer, son of Levi Satan-Lucifer and Asuna who were both killed by Rizevim. He is then taken in by Sirzechs and grows up with the Gremory household, and that's where his story begins.

Opening: Unravel (from Tokyo Ghoul)

Summary: Yusei Satan-Lucifer, a descendant of two of the original Maou who lost his family to his own grandfather, Rizevim Lucifer. With a broken past and no place to go he is adopted by the Gremory family. Will he be able to stop his two feuding Grandfathers from destroying the Underworld, stop the Apocalypse, and live his dream of becoming his father's living legacy?

Volume 1 Arc: Growing Up in the Gremory household
Life 1: The Silver Hair of Lucifer

Life 2: There Once was a boy