High casual - Advanced.
Idea # 1 - Rhiannon was born from a pack of centaurs and she was the daughter of the High Priestess (The leader) of the pack. The centaurs had a matriarch leadership as you can tell. Although she was the pack leaders daughter, she was an outcast because she'd turned out to have more dominant human qualities than centaurian ones. In fact, she seemed to be completely human, no horns, no tail (no horse qualities) whatsoever. Her pack kept her tied up daily and decided that once she hit puberty (started her menstrual cycle) that would kill her if she hadn't gained any by then. Lucky for her, she started way later than anyone else, and had time to escape into the woods before being caught.
Idea # 2 - Both our characters find themselves (incidentally) in the cross fire of two super evolved races bent on destroying either each other, or everything.
Idea # 3 - This story actually is about two young people who meet during a major war against (surprise!) Dark One/Force/Whatever. The girl is very much into fighting the Darkness till the end, whatever it may be, and the dude is kinda like, well, if the point of fighting the dark one is to bring peace, is it justified to deny yourself peace by constantly killing and witnessing death? I mean, he's against the Evil, alright, but he's not as obsessed with the fighting as the girl seems to be. She has her reasons, of course.
A Brother in Arms
Sorry I never messaged you back, I got really busy with other things
If there was no Bloodshed in this broken world there would be no need for revolution; for Vendetta.