A thousand of years ago an outer civilization came into contact with people of the earth, leading to bearing of fruitfully outcome helping them to build States, cities, even towns which brought about order and system out of chaos which gave human a taste of modern age.
As states and kingdom grew, kings and other rulers saw alien civilization as a threat which could bring them to their own slavery and demise, they declared war against them. Their dimensional gates which acted as gateways to earth were destroyed and all the crystal blood families which provided hospitality to them were told to stop their partnership or face the same consequences as their masters whom they laid their trust to; and that was PRE-WORLD WAR.
It was truly a dark era which was filled with bloodshed and battles, at last humans won the war and the dimensional gates were destroyed and the few hidden were completely closed. Crystal blood families hid their identity fearing to be confiscated of their wealth or suffer far worse fate, Skyler people who brought about civilization were no more even their course in history ceased to exist that new generation didn't know anything of them.
They remained like myth to few, a ghost to those who fought the war and a savior to their loyal one's crystal bloods.
That remained was a question, when will they come back?