Secret of the Fading light (Overwatch Story)

At first look it looks like the normal overwatch universe you know, but if you take a closer look you will find it is not as normal as it seems.
Angela Zeigler aka Mercy is not the only one of her kind, what if she got her tech from a place more ancient than you know?.
a kingdom hidden away from our reach where everyone has a valkyrie, but the catch is, the valkyrie you are born with determines you're future.
we don't get a choice, how do they expect you're wings to shine when you have broken wings.