Real gods, but they made a false world, the world that we knew, to try and make what had been imperfect perfect in their eyes. It led to a war eons before I was born, and the fallen gods were sealed away. We had to finish them off.

[Which was an almost insanely oversimplified description of what had happened, but good for short hand.]

And I would say "Kill or be killed" is a reasonable reason. Chaos meant to undo it all and start over. We decided to claim our lives on our terms, so that at least some survived.

(OOC: Hah, so the short answer is yes, in the last generation. Long answer is that every female character that isn't marriage material through the first four generations is a possible marriage partner for Rex in the fifth generation if you do things right.

In her canon - Rex married Dyshana, not her.)