New Fiction Idea #2

Now this one is actually my main original fiction at this point (scratching Macbay since I'm still world-building). It also came from Hetalia fan fiction, playing with the "Britannia Angel" concept, but I think it's distanced itself adequately.

Title: Mayflies

Genre: Fantasy

Protagonists: Jonathan and Matthew, 19-year-old identical twin Mayflies (humans cursed with wings). Jonathan is slightly more muscular and keeps his curly brown hair short. Matthew is slightly taller and keeps his hair a tiny bit longer. The main way to distinguish them is their wings (as they're not from a genetic basis): Jonathan has brown dappled wings, and Matthew has grey. Jonathan is much louder than Matthew and much more likely to take action for something. Both are outcasts because of their Mayfly status and are rather cynical because of this.

Other Main Character: Julian, 25-year-old bookkeeper/seller with circular glasses and very light blonde hair. He's not very affectionate, but he does allow Jonathan and Matthew to be sheltered in his home because of his peculiar interest in curses.

Antagonist: Knowing The Antagonist would spoil the story for you, so sorry. You could also include most villagers, since they have a tendency to chase out the Mayflies on threat of death.

Setting: Not entirely laid out. Someplace with villages—I haven't for sure established much else. It should be a rather small world, and I think I may make it a kingdom, maybe clockpunk, but I'm really not sure at this point.

Plot: Mayflies, cursed because of one or both parents' wrongdoing, are given wings; however, the problem is that all of them die before they reach eight years. Except Jonathan and Matthew... don't. Though their mother thinks it a miracle brought by her repentance, the villagers are quick to blame the cursed children for anything wrong with the crops or villagers and end up killing their father in a successful attempt to chase them away. Now the twins live going from village to village, mostly surviving through robbery as it's usually their only choice, and looking for someone named Marcus—for one of the angels had told them nothing more than to find him. They finally find a home with Julian, who even has a spell to hide away their wings, but there's a lot more to the man than he lets on. In fact, he may be the key to finding Marcus—and changing the destinies of Mayflies everywhere.

Point of View: First person, alternating chapter-by-chapter between Jonathan and Matthew.

I'm planning to start this in January for the 90-day challenge (though I'll shoot for 800 rather than 1000 words a day, and I won't be as strict as during NaNo since my fan fictions will still need updating). Hopefully it will end up novel-length, though I may have to put in some more introductory fleeing-villages scenes to do that.

What kind of chapter lengths do you prefer? My fan fictions generally have 1500–2500 words per chapter, while my NaNo original fiction had about nine pages per chapter. This is sort of an action story, so I would lean towards shorter chapters, but I'm really not sure. Input appreciated.