The Kings Blade

"When the dust settles after the Season 2 finale, Lucifer Morningstar finds himself with an unexpected new employee - Alastor, the Radio Demon, who has somehow slipped from enemy to rival to... whatever this is."

Charlie is thrilled, Hell is confused, the Sins are furious, and Lucifer is hopelessly trying (and failing) to hide how much he enjoys Alastor's company.
Meanwhile, Alastor pretends he's only staying for the chaos... right up until he accepts the role of Royal Advisor-and Lucifer's secret executioner.

This spin-off follows the slow, sharp, ridiculous evolution of their dynamic:
from snarky rivals
to political partners
to something far more delicate, complicated, and absurdly intimate.

It's a story of banter, power struggles, suspicious rings, political disasters, stolen glances, emotional repression, and two ancient demons trying (badly) to learn what affection even is.