[ Forneus' demeanour veers back to the serious. It's easy to read him - almost as if he's intentionally making it obvious. ]

You understand now that the fate of humanity on this world is decreed by the gods. They have the power to decide if a city lives or dies.

[ The answer to Rean's question is obvious. But it's not easy. ]

Gods mostly consider themselves as above humanity, as how humanity might treat insects. So, talking to them is not likely to have any effect. If you truly wish to end this mistreatment - or to stamp out any potential of gods abusing humans... then you must kill them all.