A confusing sentence from a text-based game

The context

"It was a clear cold morning, my child, and Hareetha knew she was doomed. Behemoth Mountain lay in ruins, but I could hear her laughing. For was her god not the god of ruin?"

This context is from a text-based game made by Choice of Games. I am confused about the meaning of the last sentence. It might be an easy sentence because I know the meaning of every word. But I am not an English native speaker so I cannot understand the real meaning of it.

Thanks for elaborating.

For was her god not the god of ruin?

This sentence is a rhetorical question – while it appears to be a question, its purpose is to be a statement explaining Hareetha's actions. The fact that Hareetha is laughing at the destruction of Behemoth Mountain appears strange, but the speaker is using this rhetorical question to remind us that she worships a god of ruin, which explains her behavior.

We could rephrase that sentence in a clearer, but less poetic, way as:

That made sense because her god was the god of ruin.

For was her god not the god of ruin?

While the sentence is rhetorical, it also has an almost archaic structure to it.

It can be paraphrased as:

Wasn't this because her god was the god of ruin?

The use of for implies a reason for the fact that the mountain lay in ruins.