“ A floating city hovers over the capital, seemingly appearing out of nowhere. Its spires are blinking in the morning sun, revealing alien architecture. What will happen next? Rumours spread like wildfire that this is the ancient city that once stood at this very spot. Mystics proclaim that it will take root here once again, crushing the capital under it. Somebody needs to get up there and investigate.”
“ A race of beings actually IS invunerable while in adolecence. They age, but cannot be killed. A miniority of the race (1 in 20) does not become invunerable, but rather becomes immortal at some point in thier adolecence, and ceases aging while being vunerable to death in all the normal ways. Another minority (also 1 in 20) Permanatly becomes invunerable after adolecence, but ages twice as fast as the race normally does. There is no known way to test for which of the three traits an individual manifests and the three traits cannot mix, as they are tied to the same gene, as it were.”
“ If you want to add a 'supernatural' touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.”