Yuri/Flynn, an AU where one of them is a demon summoned by the other -- maybe Flynn's desperate for enough power to make the Empire a better place, or maybe Yuri's looking to raise hell a little more literally than usual. Whoever's the summoner, the demon is not quite what he expected. Makeouts optional but awesome.

Art or fic would be equally rad; if you go the art route, I think it would be a dawn/sunset sort of color scheme (the times at the edges of things, when stuff changes!), and the flower would be a fire lily. Also focus on the demon's wings would be A+.