My Idea for a Shattered Glass AU (Good and Bad swapped). Prelude
-Once upon a time, there were two races, the short-lived humans who can roam the world freely and the immortal Pillarmen who lived long lives with strong bodies and a weakness to the sun.
-The Pillarmen hated this weakness to the sun and sought ways to bypass it, so they turned to mass consumption and devotion of humans forced them into worship/servitude and used as cattle. However this would only make them hunger and more aggressions as the start to turn against themselves.
-However One Pillarman, Kars sought a new way, working with the humans as equals for a brighter future for all life on earth. So he invented the stone mask that can make humans more like pillarmen and vice versa, bridging the gap between the two species. However the mask could only make humans a weaker species of Pillarmen known as vampires and for the Pillarmen it would unlock give potential for strange abilities they could not developed. Not removing the weakness to the latter and even giving it to the former, even giving them some monstrous qualities if unregulated.
-But before they can further develop things, the other Pillarmen found out and sought to kill him, leading Kars, and his partner Esidisi to run away along with two Pillarmen infants. Leaving the Pillarmen society to collapse in a blood-starved-fueled civil war, now with Kars and the other three as the last remaining members and the human population devastated.
-But thanks to Kars the vampires were able to use their abilities to help restore the human population, as Humans have learned to regulate and control their vampiric abilities, letting them become various levels of vampires though never fully nor in complete absence to help with their longevity admits the rubble of Pillarmen society. Later humans rebuilt their population into relative harmony and stability with all of them all containing some semblance of Vampiric blood in them. This happens while the infants grow up into Wammu and Santana.
-During research Kars hears of a Red stone of Aja which may help in mastering the stone mask. Their research brought them to Rome, a society of humans who escaped the previous Pillarmen. These Roman humans have taught themselves of a practice they’ve called Hamon; the ability to simulate the power of sun into their blood through breathing. With this power combined with the masks, a kindly tutor taught Kars and the Pillar Men how to unlock the potential of their new power, gaining powerful abilities to modify their bodies at the cost of their immortality, swapping it out with long yet still aging mortal lives. This also gave them some resistance to the sun, though it's still deadly and the length requires training.
-However the corrupt empire of Rome kills the Pillar Men’s mentor and reveals his plan to create a master race of hamon users to conquer the rest of the world, especially since they would still retain some Pillarmen blood, rendering then helpless against their mastery of sunlight energy. Even using their own Red Stone of Ajah as a super powered weaponed. Kars had to put a stop to this.
-As a precaution Santana volunteered to flee and hide the rest of the masks, and warn the rest of the humans to halt their exercise of the use of Vampiric blood, so if Hamon were to return, they wouldn't be as vulnerable. Nor could the Romans combine the masks with the Red Stone to form a weapon of ungodly power. Despite his initial hesitation, Kars allowed it.
-The battle ended up with with Kars and Esidisi slaying all of the Hamon users, with some surviving, the Red Stone was lost but their injuries had them go into a petrified hibernation. The People stopped using the Masks per Santana's warnings and even he went to hibernation as well.