@wtfkit Hi Hello, you asked me about the JayCam DKOS/ fantasy AU and I apologize, you've fallen for my trap, I'm going to reply to you with PARAGRAPHS.
Jay is the prince of Parousia, a country that's been in turmoil for centuries due to invasion from a group of kingdoms that have been in an alliance with each other for centuries(name undecided yet), which contains like, the fantasy equivalent of Metropolis, Gotham, Star City, Central City, etc etc sans Themyscira who've got their own thing but are still friendly with these United.......Kingdoms(AHAHAHAHAH). This Kingdom had ruler changes(the current JL team are the rulers) and were like okay let's stop attacking this nation we're wasting resources and we don't need to conquer their land based on a vote. So for the past 20-ish years, they're on somewhat friendly terms.
Jay met Jon during an annual visit to like, an event held by this, Allied Kingdom-Country situation when they were around 10-12 ish and became friends. They hung out often and the noblemen of the Allied Kingdom-Country situation(seriously, a name, need one) are honing in on this because why bother with invasion if they could just set an arranged marriage between JayJon and get things rolling? There's lots of discussions and feuds, a huge dramatic JayJon love story wrt succession and all that, and it's decided Jon's gonna go to Gamorra and Otho will take over after Clark. During these visits, they also befriend Nia who's the second daughter of a Duke and Duchess whose family is famous for their prophetic powers.
Jay goes to visit Jon during the succession problem.
Cameron's almost the same as he is in canon, his mother came from a poor family but had caught the eye of nobleman. She abandoned Cameron to marry into that man's family and ever since, Cameron has been roughing it on the streets. He got his powers when he stumbled into a magic ritual by a group of nobles who were opposed to the power transition when the JL came into power in their respective kingdoms and got powers which allowed him to control cities. He doesn't do much with it, doesn't want to. He wants to stay as lowkey as possible because magic's a bit of an on-demand resource and he wants nothing to do with nobles.
He travels across the lands, and he's known for his uncanny ability to find anything and navigate anywhere without getting lost. He makes a bit of money like that, and he's often quests to find precious things(and he pickpockets).
One one of Jay's visits to the Kent fam's Kingdom, he decides to go exploring on his own and gets lost. He asks around and finds Cameron. Cameron is reluctant, he doesn't trust the royalty in any capacity, but Jay's charming enough and he knows they've been invading Parousia previously, so he shows him around(with a level of reluctance). Once Cameron shows him the palace, Jay sneaks out sometimes to go wandering on his own and asks Cameron to show him around. Their friendship is brief, but they bond and then comes time for JayJon's wedding!
Because there's a coup and a conflict between the ruling houses and the noblemen and everything goes to shit with a massiv civil war! In this chaos the people doing the coup decide to invade Parousia once more. Parousia is small, they were already exhausted fromc centuries of fighting the allianced kingdoms off and they had let their guard down a little after the engagement was finalized between JayJon but the coup never respected that. Sara dies(Jay doesn't know that), Jay's taken prisoner, Parousia's invasion is led by Bendix. He takes Jay to experiment on him with magic for months on end and he gets the phasing powers. He manages to escape, and because he was held captive in Metropolis, he knows Cameron's around. He goes to find him in the hopes he'd help him Jon.
Cameron does help but on their quests to hide from the soldiers roaming the cities and reaching Gotham which the families were using as their base, Jay learns that Nia had (been forced to) help the people leading the coup to invade Parousia with her prophecies. She had managed to escape and rejoined Jon and the others to help the ruling people. When they arrive, Jay's angry. Jon promises to help but after shit in the kingdoms have settled and he offers for Jay to stay with him.
Jay's like "fuck you, engagement's off". Cameron kinda starts falling for Jay during this whole trip but he'll never, ever speak of this because as the Fairy Godmother from Shrek put it; "She's a princess, you're just some guy" is that how it goes? On the return trip to Parousia, Jay's entering his mentality pre S6. He asks if Cameron wants to come with him because during this whole trip, they both tell each other about their powers and bond over the loss of autonomy. They have a common enemy(ish). Cameron decides to go with him with no real plans, he was always moving around anyways and had no attachment to the Allied Kingdom's lands so he goes. AND THEY FALL IN LOOOOOVE~~
I need to think more on the Cameron aspect of this setting, I feel like I keep neglecting him for Jay. A random civilian who befriends royalty of another kingdom, fast forward like 15 years and suddenly he's prince consort(not really, Parousia technically doesn't have monarchs, but a leader elected by varying clans who rule for as long as they live and then the elections start over again).
I haven't really thought too much about a story or anything. Hope this answers it!