The Banished Realms, also known as Hell, is an ancient dimension that is as old as the UUniverses itself. 4 billion years ago, long before Earth itself was created, the Elder Gods of Creation created the UUniverses and the worlds of which they would divide up amongst themselves equally. But there was one dimension that no one wanted: Hell, a prison world for the souls of the damned who chose to follow evil in an effort to gain power in the worlds. In this world, fire and brimstone were the terrain while volcanoes and blackened skies with falling meteorites proving to be deadly obstacles for anyone who dared to visit the place. Since no one wanted to be in charge of this deadly world, the elder gods quickly gave to the job to the one unwilling member of their Council, Chernabog, God Seeker of the Night. Chernabog wanted more than what he was given, and began the First Cartoonian War to conquer the entire UUniverses. In the end, he and his forces of evil, known as the Darkspawn, where all captured and thrown into Hell as punishment for their insurrection against the worlds. Because he owned this world, Chernabog was the only one who didn't truly get thrown in, and doing so would only cause his great evil to break out of it in a millisecond. Instead, the Council chose to seal him away in a dead world known as Bald Mountain so that his evil would not try to take over the UUniverses again. As for the Darkspawn lords being sealed away in Hell, the High Council placed a heavy lock on the Gateway to Hell so that only a person of the purest heart could open the door and never a demon looking to free the dark lords. To this day, many individuals have forgotten the true nature of Hell, and only know the name 'Hell' means something bad and could cause bad luck to happen. So they renamed the terrible place 'The Banished Realms' (A more kid-friendly name). It’s later revealed that the Banished Realms has an expanded society containing all the iterations of hell throughout fiction, most of which aren’t loyal to the Darkspawn or are vilified by them. One of these iterations is that of Hazbin Hotel/Helluva Boss, which despise the Darkspawn for long making hell look like just a place meant to punish those who commit sin, that while they're perfectly aware that they're no improvement themselves, felt like CAUSE of the Darkspawn that heaven feels incline to adopt double-standard extremes like the advent of Exterminators, but in truth, Heaven and Hell are both neutral realms, since neither side is completely good nor completely evil. Their respective jobs just paint them as such. Additionally, the Banished Realms was once just referred to as just the place with incompatible or excess realms that couldn't fit within the grander universes and/or with excess fire wasn't Firea levels of manageable.