Eva Stratt as a religious character is an inspired choice.
But not in the "I will be punished in hell for my sins" way.
In the "You are sending another flood? You doubt us? I know what we can do, we have all the tools if we just try. And you know it, and I know it. Challenge accepted" way.
She's not building an arc, but she's building her ship of faith.
When she must send Grace, against his will, she is angry. But she never wavers. "I believe in him too. More than in my own emotional comfort."
So many people die, and die horribly. And Eva Stratt remains locked in a staring contest. "We will persevere. Throw whatever misery you want. We can do it."
And then she is proven right.
"But why? Why did this have to happen?"
And there's no real answer. There's only what she did in response, what they all managed to do, and the fact that she was right.