Figured I might as well write down all the AUs my friends and I have come up with, so they're under the cut. They're mostly Kirkoma or solo H-based.
Kirkoma highschool: Socially-deficient bookworm Joshua settled down at a table in the school library one day, not noticing the only other student in the room. Soon enough, with his nose buried in his book, he caught the attention of the school's resident stoner, Sanae. After the first few moments of creepy staring and absently reaching into his bag to devour a sheet of paper, the clearly-high student seemed to become enthralled with the lions in the nature book Joshua was reading, going into a disorganized rambling of facts that sounded to come straight from a nature documentary. After the random stream of information, he pulled out a sketchbook, revealing to Joshua that he was skilled at drawing, particularly big cats. Focusing his attention on a half-finished drawing, he asked Joshua whether he had any food on him before casually reaching into his bag without any further questions, feasting upon the snacks formerly belonging to his newly-dubbed 'friend'.
After that initial meeting, the two began spending more time together, most often at the insistence of Sanae. It didn't take long for Joshua to bring in more food to calm his friend's munchies, snacks soon turning into full-blown lunches. In return, Sanae's presence seemed to dissuade the school bullies from harassing Joshua, the tall, lanky teen appearing to be threatening despite having the attitude of a sentient teddy bear. Their high school days pass by in such a manner, the introverted blond appreciating the singular, yet bizarre, friend he had made, even if his personal space was occasionally violated by Sanae's craving for snuggles.
Pharaoh Josh (Super undeveloped): In ancient Egypt, Joshua rules as the pharaoh at the tender age of 15. However, behind the young figurehead of the prosperous nation is the true power driving the country, Sanae Hanekoma. While secretly taking the advice of the far more experienced man, Joshua sits at the throne, taking the accomplishments, and responsibility, of being in charge of the still-growing nation.
Kirkoma pirate (Super undeveloped): Pirate captain Sanae Hanekoma kidnapped a high-ranking citizen, Joshua Kiryu, in hopes of winning him over to his side, figuring his companionship would go over better than one built with another, probably untrustworthy, pirate. Despite the frequent protests concerning Sanae's choice in clothing, speech, and poor hygiene, Joshua has settled into life onboard the ship, secretly enjoying the company of his rough-mannered, yet jovial, captor.
Bitty Josh (More a chain of cute little events than proper development): Sanae adopted Joshua at a young age and cared for him as though he's his own son. He attempted to keep the child out of the whole Game business as long as possible, only giving vague details about why he has to work on 'boring things' so often. With such little information to go off of, little Joshua vowed to eventually free Sanae from his boring, hellish job. However, with both Joshua's powers to see the UG and with how often Sanae has to work with the Game, it didn't take long before he had to reveal what he was to his adopted son. Under Sanae's (occasionally inattentive) care, Joshua grew up to become Composer, fulfilling his vow he set in childhood.
Kirkoma role-reversal (Semi-developed and thought up a loooong time ago): Rather than Joshua being Composer and Sanae being Producer, the two have switched places, Joshua being the sassy, yet dependable Angelic barista while Sanae is the no-nonsense ruler of Shibuya. Due to Sanae's serious nature, Joshua delights in teasing the young Composer often, using his Angelic powers to swap his gender from day-to-day and fluster him. Hugs are another favorite of the Producer, Sanae not appreciating the close, sometimes awkward, contact brought about by Joshua suddenly yanking him against his chest. Though the teasing occurs quite often, they do share rare moments of more serious friendship, the only ones Sanae is able to indulge in.
JoshNeku highschool (Put to use here): Used to the life of a pampered homeschooled student in the country, Joshua had to acclimate to life in Shibuya when his family was forced to relocate there for his father's job. Rather than be homeschooled in comfortable seclusion, he had to attend the local high school as his mother, his former teacher, had to take on a job in order to deal with the increased cost of living in the city. He quickly found that his body did not appreciate life in the city, his already-weak immune system further falling apart due to the smog polluting the air, making him frequently become ill. As such, his parents agreed to have him stay after school when he was healthy in order to catch up on work that he missed.
In the room put aside for him after school, Joshua found it more intriguing to harass the only other student with him rather than focus on his assignments. When said student, Neku, finally protested against such actions with the excuse that he had to focus on his work, Joshua grabbed his assignment and easily completed it for him, used to harder problems when his mother taught him. After that, the two began speaking outside the time spent after school, first about homework, then steadily branching out to hobbies and the like. After a school year of this, the two realized they had grown mutual affections for one another and began going out.
Nurse H: Genderbent H who's wanted to own a cafe since she was little. However, her parents wanted her to 'actually do something good with herself', so they sent her to med school. Not having much of a choice, she dove right into the work, eventually graduating a becoming a nurse. During her studies, she learned that one could make a potentially pretty penny selling organs on the black market, so she does just that on the side, luring men charmed by her looks to secluded areas with promises of free physicals and the like only to sedate them and liberate them of their organs, all for her dream of owning a cafe.
Kirkoma cop: Sanae is an officer for the Shibuya police department while Joshua was a perfectly-upstanding citizen. However, upon setting eyes on such a fine officer of the law, Joshua knew that he simply had to have him for himself. So, what does one do in order to catch an officer's attention? Go up and talk to him? No, Joshua Kiryu chose a flashy, unforgettable way to catch his attention and set a home ablaze. He willingly accepted arrest and bothered Sanae from his cell during his rounds. Escaping from his cell one night, he followed Sanae to his home and slipped into bed with him, much to the surprise of the drowsy officer. Though he's continually bothered by the convict who keeps worming his way out of jail, he's kept up a cold front, not giving in to the criminal's flirtatious nature.
Evil!H (Undeveloped): Basically, Sanae if he abused his multitude of Angelic powers. Using the power of brainwashing pins, he's altered Shibuya for his amusement, overpowering the Composer and his underlings to serve him. Whenever the Higher Plane pops down for a checkup visit, he makes absolute sure that they only receive good news about how the city and Game are doing, not wanting his tyrannical reign to end prematurely.
H twins: Born in 1965 when infanticide was still practiced in Japan, the twins were abandoned in a forest, the superstitious mother holding the old belief that they were possessed by an evil spirit or something of the sort. There, they were discovered by an infertile housewife and taken back to her home. Instead of the joy she was expecting from her businessman husband who had wanted children, she received only rage and scorn, being told that he wanted children of his own, not demons she plucked from the forest. However, he allowed them to stay, only so he wouldn't have to deal with the inevitable weeks of sorrow from the woman who always wanted children.
Though their childhood was spent in upper-class comfort, the twins received little emotional support, their mother too busy complying to her husband's demands and their father unwilling to provide it altogether, thus they sought each other for company a good deal of the time. Eventually, they found a stray black cat that they took home and named CAT, branching their affections out towards it as well. The younger twin, nicknamed 'H', had a tendency of always feeding the cat whenever it mewled for food, putting him in its favor and aggravating the elder, Sanae.
As they grew, the normally quiet younger twin formed a vicious protectiveness over his brother, going so far as to assault people who he deemed were becoming too close to Sanae on occasion. After a particularly nasty fight occurred due to that possessiveness, he was sent to a psychologist and, when a particular pattern of alternating aggressive and depressive behavior was nailed down, he was diagnosed with bi-polar and put on antipsychotic tranquilizers to hopefully lessen some of the mood swings.
Everything seemed to settle into normalcy after that until it was the twins' time for art college. Now away from the watchful eyes of their parents, H secretly stopped taking his medication due to the potential side effects, namely decreased life expectation. Being prodigious in the art field, they easily completed their assignments, leaving plenty of time to experiment with their affections towards one another and the seedier aspects of college lifestyles. They took up recreational drugs when they could acquire them and visited a local sex shop for its wares. There, they befriended an intern who was in a few of their classes, Joshua Kiryu. Over time, Sanae became rather affectionate towards him, much to H's rage. However, he now knew better than to put up a scene about it and ruin his brother's happiness, so he kept his mouth shut about it as much as he could, alternating between worrying that Sanae would abandon him for Joshua in his depressed moods and furious that he had taken a fancy towards Joshua in his manic ones.
The Hs soon graduated from college, hiring Joshua as their PR manager and lover as they made their own niche in the art world. They quickly became famous, their differing styles worming a way into the public's heart. As they paved their way to fame, rumors cropped up amongst their fans of the possibility of them being in an incestuous relationship. To keep their image as pristine as possible, Joshua stamped out such accusations as much as he could, not helped in the slightest by the twins alluding to such things during interviews.
Their relationship was only made public by Joshua after their deaths by cancer in 2044, something that they agreed to have released only after they died. Due to their particular skills in art, the Higher Plane turned them into Angels with their consent, leaving them to encourage budding young artists who have been put into the Game. However, I've come up with quite a few 'bad end' AUs where this doesn't happen.