Once, a powerful family, the Sinclairs, ruled over the earth. They led a religion based upon light, incorrectly stating that there was only light in the universe. The two founders of this family had eight children. One of these children, Elizabeth, was incredibly smart, and noticed a mere day after birth that light could not be the only thing in the universe, as then what were shadows? On her 17th birthday, she dared to ask her father this question. He then turned to her, a look of rage in his eyes. He threw her over the balcony, yelling "Come back when you have seen the light, heretic!" as she plummeted. She survived the fall, and sought to learn more about shadows and darkness. She eventually learned of Necromancy, as well as the art of the Assassin. Through this knowledge that she found of darkness, she crafted herself a mask made out of a dead man's skull, woven together with shadow. Even now, she stalks the night, ever searching for her father so she could plunge a dagger into his throat.
Name: Elizabeth Sinclair
Element: Shadow/Death
Primary Weapons: Crossbow shooting bolts of shadow, Twin daggers made out of slivers of moonlight, glass shards strapped to arm

Inspiration for glass shards: Hidden blades from Assassin's Creed
Inspiration for skull mask: Corvo's mask from Dishonored