Just like the prior Ref image, art made by  Ratafari and some other help with overall design+Origin story

Long ago lived a very powerful mage named Pyrow, his powers in magic rivaled combined strength of entire kingdoms' armies! As the mage's power grew, so did the concern that the mortal realms' kings and queens feared the rising strength of this young mage. Fearing he would begin looking for more than just wealth and respect, thinking he would want his own land to rule. In time that fear became a reality as the mage began making moves to have his own Kingdom. The Gods held no concern for the “powerful mage” roaming the mortal realm as he was nothing but a bug to them. Royalty in the region began begging and pleading for the Gods to intervene, but they didn’t mind petty pleas. So they turned to the religious leaders that helped them to convince the people to think that this mage was a pagan villain that would drive this land into a horrible state, as the plan worked the pleas to the gods started to be heard loudly by them, so much that the Gods grew tired of these pleas. The king and queens of the mortal realm invited the mage to a ceremony, tricking Pyrow into coming to a trial where in the Gods themselves smited him. Banishing his soul to eternal damnation in the underworld!

Awakening in the afterlife, Pyrow arose to find he’s surrounded by towering demons. The demonic creatures ranging from two heads taller than the six foot sergal to nearly double his height! Each of them ready to torment the sergal for all time. The desperate mage instead fought back before they could capture him! Using his mystical powers to control the minds and spirits of the large snarling demons! With the group of monstrous beings at his beck and call he plots his return to the overworld. Using spells of alteration he attempts to hide himself and changes his figure from sergal to hybrid demon. Black horns with gold ribs sprouting from his head, gold morphing into the red fur on his face, and wings growing out of his back. His transformation was complete and he no longer had to fear the demons all around as many of them began to respect and follow him as his leader without being commanded too. He discovered that some of them liked his feminine and voluptuous appearance; this only stroked the newly formed demon’s ego.

Years go on and Pyrow learns more about Hell and the demonic races that inhabit it. Split into two, between the brutish ‘giants’ with their priority to punish the mortals sent to the underworld. Then the more average build demons who seem to act almost akin to those of the overworld. Of course, both of the demonic races carry many of the demonic features unique to the underworld. Fur mixed with feathers and scales, horns, fangs, and exposed thorns. Yet they are terrifying in appearance they aren’t quite driven to torment like the more physically powerful ones.

With his newfound knowledge he begins his slow and methodical take over of the underworld. Winning the hearts and minds of both sides of the race. The brutes with his attractive appearance and terrifying magical power. The more civil in nature demons with his ideas to change Hell into more of a civilization. It did not take long until he became popularly known as the Demon-Queen. A misnomer at first that made him feel embarrassed by it! He was certainly a man and nothing would change that, he didn’t want that to change. Yet something about the title suited him… It resonated in his mind and gave the feel of power, elegance and dominance over this gods forsaken land. One that created a symbol of salvation for the damnation of the place. Great for his own schemes. With this in mind he did not change it. Rather, the demonic leader embraced the name. Pyrow the Demon-Queen.

He loved it.

Having a proper title and leadership over the demonic race Pyrow makes his move. Starting off small at first, constructing towns and then later on cities for the demons. Pyrow still letting the brutes do what they do best, tormenting the lost souls of the sinners and -now and again- build or guard. As things went on though, Pyrow grew curious as in his prior travels of the underworld he came across many lost souls. Most seeming to certainly belong when they confessed and entrusted him with their history. Others too terrified to speak to him… So oddly out of place for the characteristic way of the common sinners, that made him grow curious of why these faithful people ended in this place. Wanting to find out more about the souls that enter his domain Pyrow developed a new spell that allowed him to look into the history of these lost souls. Discovering some were sent below for utterly pathetic reasons! A few akin to Pyrow, having angered the wrong people, some simply blasphemers who spoke out of turn, of course the Gods above were cruel at times. Pointing this out in a drunken stupor and getting gutted over it certainly wasn’t reason enough to spend life times in constant torment. With great effort the Demon Queen began the process of separating the just from the unjust in his underworld. Showing some demons with innate magical abilities the spell. It became their job to find and ‘rescue’ those being unjustly punished across the hellscape. Of course there were still those who certainly belonged and deserved a few life times of punitive punishment. Murderers, rapists, gluttonous thieves, and even more kinds of barbarous deviants to name in the eternal list of damnable sins.

Over time sanctuaries were built by the brute demons for those unjustly punished. If capable, he would give these souls a better life as a resident of the underworld rather than a soul to be tormented. If possible he’d rather send them to Heaven, yet despite his strength he couldn’t manage opening a portal to the land of gods. The least he could do is save others from being damned. Through deals and favors with the Gods he became the judge of the underworld. Choosing the fate of those unfortunate enough to pass on from the mortal realm. Sending them to heaven, the deepest darkest corners of Hell, or perhaps even back to their realm if their doom was deemed to be so unfair. However he could not send them back to the overworld if they were sent by the gods to be damned to Hell there was nothing the Demon Queen could do. Not even a portal to the overworld could save those damned to Hell. No matter the means of their damnation.

Centuries pass with Pyrow at the head of the underworld. With size alteration, portals, and powerful fire magic he continues his rule. Those powers growing in strength to the point of practical god-hood. Through passive regeneration magics he may rise like a Phoenix, with his demonic features that once adorned to blend in with hell’s population no longer being simply looks. These characteristics fuse with him to the point of true conversion into a demon, accompanied with the strengths, and few weaknesses, of one.

After all this time the landscape had changed dramatically. The raging fires covering mountain tops and fiery oceans had come to an end. Vegetation even began to grow in the cities and countryside after he went through the trouble of collecting plants in the overworld and bringing them back. Things looked normal compared to when he started. The skies were still a wash of orange, yellow, red, and at times a dark purple in the realm, and fire was still abundant; it wasn’t anything devastating. There were basic things natural to the realm that could not be changed. Yet inside the cities he built were gardens, greenery that demons had never seen before. Towering buildings, and businesses. He had crafted a civilization. It had taken much work but after so many hundreds of years Pyrow had what he wanted. He was the leader of a region. No. Not a region, an entire realm! The capital now housing an enormous palace for him to live in. Filled with willing servants and handsome guards. Eye candy for the Queen and his guest, of course, as he personally had no reason for anyone to guard him. Practically being a God with his spells and demonic strength.

Finally satisfied with how things have become he rests on the balcony overlooking the land. Purple drapes and tapestry adorned with gold all around. Gold jewelries covering his body. He loved it. Even having a few mortal ‘friends’ and one particular mortal he considers more than that~. It was wonderful, Hell changed over the course of a thousand years from a horrible fate to an entire civilization. Booming with cities, businesses, and even working with the overworld. The tech of the modern era of the overworld mixed in with Pyrow’s magic. To the once mage now Demon Queen it was his own little Heaven. Spending much of his days on his gold and purple throne -or at times resting in the coiled tail of a large naga guard- passing judgement onto a select few souls. The Demon Queen surrounded by towering muscled guards that vary in forms of anthropomorphic bulls, dragons, wolves too many, many others. Even sea creatures such as sharks, just with a demonic twist to them. The varying races of the demonic underworld as well as lost souls turned willing servants.