An Incubus is a sex demon, plain and simple. They feed off of the sexual moods of humanity. But once humanity found out the Incubi existed, a big war started to get rid of either one species or the other. But there's a problem. Succubi (female counterparts of Incubi) and Incubi need the sexual energy of humans to fuel them, and the men of the human race are dying very fast due to war depleting resources, and everything went to the women. Without men, the human woman can't reproduce and therefore can't supply the demons with the sexual energy needed to keep the demons alive. So some sort of alliance has to be made, between the king of the Incubi and the queen of the humans. An alliance that requires marriage.
Now, I've had too many people asking ridiculous questions. Here is the plot but stripped:
There's a male character, the Incubus king.
There's a female character, the human queen.
Obviously there will be challenges in this arranged marriage because the humans think Incubi are disgusting, and inappropriate, and just much too uncivilized. They aren't, but you know. Humans can be morons.
MOST IMPORTANTLY:
This is set in a Steampunk kind of setting. Women wear dresses with corsets, men wear trousers and poofy shirts and weird vests, and there are advanced machines but no over-advanced weaponry. The most advanced tech is low-tech plumbing.

It’s the year 2285, and the world is in turmoil. The U.S. Has been shunned by the rest of the civilized world and has become a dictated union. Global warming, world wars, and economic collapse have turned the States into one of the most dangerous places to live. Only 1% of the population is wealthy enough to have homes, cars, decent food and clean water. The rest of the country is living in half-homes and has to scavenge every meal.
This dictatorship locks away dissenters, the sick, the old, and the mentally unstable in concrete prisons underground. The food is poor, the living conditions are nowhere near humane. One girl among these prison outcasts is treated especially terrible. At a very young age, she developed a power that made it impossible for anyone to touch her skin. The government didn’t know what to do with her, so they tossed her in prison to let her rot. Now, ten or more years later, the government finds that they need information about a certain Resistance group. They can’t torture it out of the prisoners in any traditional way… so what if they use her?
They send their young, up and coming general to collect her. He enters her cell to find a mad creature, incapable of speech and the most basic human interaction. He thinks her a beast, a monster for her curse and the job she’s given. But will that change in the next few weeks as he wipes away the grime and teaches her how to be human again?

Girl: You wake up in a castle, and you don't know where you are. There are so many things out of place, and your memory is blurry, so you really just have to connect the dots. It's not that hard once you notice a few key things: Your clothes are gone, replaced by terribly revealing underwear. Oh, and there's a man sleeping beside you. After learning that you've been gifted to this pervert as some sort of toy, you rebel as much as possible.

Guy: You're the Crown Prince of (some kingdom) and for some reason, you’ve been given a slave girl to do with what you please. You aren’t a very nice person, but you aren’t a monster. You do your best to wrangle this girl into submission but she’s like some wild beast.
And things progress from there.

(I have drawn some maps.)
Okay, so a lot of the northern kingdoms (Eskal, Ardany, Essea) worship Twelve Saints and Three Devils. The Saints are all people who once lived, and did great deeds that lived on to teach a lesson. The Devils are the opposite. They're the negatives, people who did horrendous things in life and now control the Abyss, what we might call Hell. We can introduce the deities during the roleplay.
Noxus and Ardany have been warring on and off since they began. Ardany has well-protected lands and an abundance of precious resources that most haven't even discovered, while Noxus, to Ardany, is nothing but a boiling cesspit filled with murderers and liars and cheats. Noxans think Ardanians are as cold as, if not more so, than their country and the frozen wastes to the north of it, and they should come down from their high horse. Ardanians are quite content with their territory. Noxans keep provoking them into war. It's safe to say tensions are high.
Banti is neutral and will either help both sides in times of war or will help no one at all. Kiba is nothing but jungle, allied with Noxus, and home to slave-worked coal mines. Xiang-Bao is allied with Ardany and are famed for their warriors, making Ardany near-impossible to invade except through Oldwood, which is famously dangerous for misleading armies and sheltering monsters of nightmare. Genta is allied with no one and hates the squabbling of other countries. It's too small to invade any other kingdoms, so the poor Gentans must be content with their freezing cold rock in the middle of nowhere.

Girl: Your parent(s) die. Filled with grief and anger, you are sent to live with your uncle/grandma/some other relative in a tiny town in the middle of a ridiculously dense forest. You are told never to go into the forest at night, and especially not alone. But filled with rebellion from your parent(s) death, you go in there anyways. You run into a man, a man who has the ability to turn into a wolf. He kidnaps you, and shows you his pack. Your world is turned upside-down by this shocking revelation. You're being pulled and tugged in a million different directions, and through it all you fight through your growing attraction- and fear- for the man who took you, even though he's more beast than he is human.

Guy: You're a werewolf. Not the bitten kind, the born kind. Your pack lives in the forest surrounding the town. There's a treaty that basically says that the werewolves will leave the townspeople alone and vice versa. But if a human enters the forest, they belong to the pack. One night, while you patrol, a new girl to the town enters the forest and you claim her before your pack mates. You show her your pack, keep her safe from the harsher wolves, the ones that dislike humans. Along the way, you discover for the first time exactly what it means to be human.
Also, I have a thing that must be explained.
You know the inner voice everyone has, like a conscience that tells them right from wrong? Well, werewolves have that too, but theirs is broken. They don't have an off switch, and their inner voice is angry, horny, and slightly violent. It's also very persuasive. Depending on how a wolf is raised, that voice can either be tamer or wilder. When the inner voice is wilder, it's harder to ignore, thus creating a werewolf that is moody, easily frustrated, and a bit bipolar. Someone who is harder to control.

Important stuff:
These werewolves are, for the most part, just human beings that can shift into wolves. They don't have an extended lifespan or slowed aging. They are slightly stronger, but not to an insane degree. Some of them have a strong enough sense of smell that they can scent things a few miles away, or scent moods and emotions. This is rare, though. They just look like really big, but otherwise normal, wolves.

Girl: You're a princess. In your kingdom, magic is just barely tolerated and your father is trying to get rid of it. But you yourself possess magical powers. You've been kept away from people your whole life, an embarrassment to your royal family. One night, you run away. You travel a nearly impossible distance, even across an ocean, to find the son of a powerful sorceress who you believe can teach you to control your power. But what if it turns out he doesn't want to?

Guy: Your mother was the most powerful sorceress in the world. A true legend. And because she was the best, she raised you to be even better. No child of hers could be anything less than perfect. She treated you cruelly, punishing you with her magic when you made mistakes or refused to learn. You've come to despise all magic-users and magic itself, causing you to never use your own powers if you can help it. Then, a girl comes to you, desperate for your help. She's so young and naive. She won't survive on her own if someone doesn't teach her how. But how can you teach her to control her powers when you hate yourself for having the same gifts?

Okay, so basically the zombie apocalypse happened almost twenty years ago. No one old enough to remember First Night talks about how it all happened. There are fenced-in settlements all across the ruin of America, some of them large and some of them small. People lock their bedroom doors at night in case of death, because no matter how you die, you become one of them.
The world outside the fences is called the Rot and Ruin. Most everyone pretends it doesn't exist. They're content to live inside the walls, like cattle. They're in denial about how the world is now. Except for a few. Bounty hunters, souls so damaged by this new world that they just don't fit in with everyone else. Killing their targets- not always the zombies- is all that gives them peace. And not all the bounty hunters are good. Most are corrupt, evil. But there are a spare few, those who call themselves 'closure specialists' that hunt zombies that people knew in the world before, and putting them to rest in the most humane way possible. Then there are Loners, those who live in the Rot and Ruin and carve out their own niche of hell. They're territorial and vicious, and often kill on sight.