Alastor

Some facts about Alastor:
During his lifetime, he hosted a radio show and died in 1933.
Having entered Hell, in one night he overthrew many of the lords of Hell who had ruled for centuries.
Seven years later, he appears in Hell at the doors of the Hazbin Hotel, which is under the control of the princess of Hell, Lucifer's daughter, Charlie Morningstar.
Alastor offers to help her manage the hotel, while trying to free himself from his own deal and fighting his technological rival, Vox.
As a Sinner, Alastor is biologically immortal, as he cannot die from disease or other natural causes, and he cannot age.
Can summon and exit his demonic form at will.
He has a high intellect and is skilled at making deals, which is why he became one of the most powerful Lords of Hell.