Kol is delusional. Perhaps by the influence of some meddlesome, evil, former Pharoh?
The people of the "soon to be" Sunken City were wicked evil doers getting their just deserts after having foresaken all warnings. Perhaps by the influence of some meddlesome, evil, former Pharoh?
Anephas was too weak after having JUST been resurrected by your powerful band of heroes, while Cet's been building his power for some time before your heroes entered the scene.
+Dr.Pick