I don't often write out his backstory, but here goes:
Jurao is the son of two famous beast hunters - a nomadic people of the Demon Realm that hunt the most dangerous animals in the realm both to keep them from overrunning settlements and to provide the extra meat and pelts to settlements, particularly small villages outside of the large cities. His mothers died when he was young, and he was sent to live with his aunt, a blacksmith in the Demon King's Castle.
While he apprenticed under her, Jurao wanted a way to be closer to his mothers - so when he became an adult, he joined the army. His aunt, who stopped making weapons after a falling out with her sister, made him a pair of swords to match the sword style of his beast hunter family - as a sign of her blessing. His extreme skill in combat soon won him an officership, which also earned him the lowest rank of nobility in the Demon King's court, as is traditional.
Jurao soon became the clear intended successor of the Demon General of the time, and after he took over the position, became the first Demon General to never be defeated by the human Champions - summoned from another world, and sent by the Empire due to ancient conflicts. He formed a close friendship with the Demon King - and was nominated to be King Ergirri's successor by the man himself. He won the tournament known as the Royal Trials, giving him access to the Thousand Caves of Torment - which he also overcame, and gained the Greater Blessing of Ascension from the demon God of Kings Maenscul - increasing his already impressive physical abilities tenfold.
By kingdom charter, the cities of the United Demon Realm - the main hubs of their society in a hostile landscape of carnivorous plants and dangerous animals - have the right to declare intent to cede when a new King takes the throne. Several did - some thinking Jurao's military background would make him a militant King during a time of long peace, and others opposing his common background. Others, however, abstained for the same background - as beast hunters and blacksmiths are the two oldest and most respected professions in the realm. And Jurao's other half of his family are one of the famous families of the city of blacksmiths - preventing that city from declaring intent when they normally would have.
To successfully cede, a city must hold out for ten days during a siege by the Demon King. Jurao traveled the realm, and defeated each city within a day - save one, which took two. And when he returned after the thirty years it took, he found the castle gardens had a secret caretaker.
Jurao is very autistic. He speaks so monotone that he fails to put the proper enunciation on questions, and expresses extremely little through facial expressions. Combined with his large size as a trollish demon, reputation as the "Beast of the Battlefield", and being a solid slab of muscle, many found him intimidating and hard to approach... until he took seventy years to pick his department heads, who serve as his inner circle of advisors. He took the time to attend meetings in every department, and even smaller branch meetings. He conducted interviews with not just those looking to fill the positions and the current department heads, but the current branch heads and staff members, wanting to ensure he chose the best people for each position regardless of rank. This careful and considerate approach made most of the castle staff see him with more respect and less fear, though the noble court did not think much of it.
In this same manner, when he heard out Braelin the human gardener that had been caring for the castle gardens for the past decade, he made the man the new Royal Gardener so he could continue his good work with proper backing. He didn't consider how the court would react - as his department heads and singular valet - his best friend since childhood, Feyl - handled the court on his behalf even though he had only been appointed for a century, and he had little direct involvement as General. A very short time for the long-lived demon species.
Jurao is over 1500 years old - the demon equivalent of his forties. He's curious, which may be the influence of his patron deity, Nosu - the Deity of Wisdom. Demon patrons are determined by the circumstances of one's birth - in Jurao's case, being born outside of a settlement or camp at night, due to Nosu being seen as the smaller green moon. He practices lockpicking - picked up during his time as a blacksmith apprentice - as a hobby, with his aunt gifting him new complex novelty locks once a decade to try and stump him. He's introspective and often quiet - sometimes, I realize I've written an entire conversation without him saying a word as he just listens and thinks.
Jurao has also never been romantically or sexually interested in other people - which leads into the plot of the slice-of-life romantic comedy he's the main character of, which his backstory clearly matches completely flawlessly.
Bonus fun fact - when he was a kid he heard a story about silver fish eating certain metals and becoming dragons, so he spent almost a century feeding any silver fish he saw various minerals to see if one would turn into a dragon. (Spoilers: this is not a thing.)
