Nice. But you may have left a room un-explored.

Gods incarnate as humans for many reasons. Many, like Zeus, did it to get laid. Others did it to kick but, or to, as your character does, to give a warning or a prophecy.

One of the interesting concepts of ole JC is that he took the form of a human to try and understand the universe from the perspective of his creation.

The searing pain of being mutilated by lead projectiles could be the moment of epiphany for the guardian into why humans act as they do. They'll do anything to avoid that kind of pain. Or the pain of starvation after a ruined crop. Or the pain of the loss of those close to them.

The final twist however, is that the guardian only experienced the pain of being human in that moment. She's watched the planet long enough to know that humans also experience joy and love with an intensity opposite to what she experienced. But she'll never get to experience that human trait.

Then, the whole idea of free-will comes crashing in when she realizes she can herself blame God for her pain at not having experienced the joy of being human.