Monstrosity Divine (слэш)

After declaring himself God, Castiel realizes that Hell is a necessity and a strong leader is required to maintain the damned souls. Discovering Crowley's betrayal, he deposes him and decides to put one of his own kind on the throne of Hell, and who better to manage Hell than the first fallen angel? While initially mistrustful, Lucifer is content to allow Castiel's newfound powers to work to his advantage, but he soon notices that there is something distinctly off about Castiel. The souls from Purgatory are driving him mad, and something else is lurking beneath the surface, hiding within him and waiting for its chance to take control, pushing him ever closer to an inevitable end.