In one of the recent threetoe stories, the magician charged into the afterlife at the pyramid (Really confusing) but he sort of stopped armok.
Maybe once a fortress becomes SO powerful, or an adventurer becomes SO godlike (i.e HolsticDetective type of powerful) You could go into the other realm and challange the gods themselves, or maybe your fortress could eternally be part of the heavens, risen up from reality! This would also give gods actual events, making them more interesting. (this could tie in with the otherworld/afterlife sort of)
Now, how would you beat a god? Add two mechanics (Or improve their current versions) of Faith, and Belief.
The difference?
Faith would be more along the lines of "I believe that X will save us!" or "X is the most powerful!" More like worship.
Belief is the system of believing something is there, but not really worshiping it.
So if your a really pimped out adventurer, Urist McHolstic, and you save some city from a siege, people will start to have faith in you, believe you are powerful. Ten years later people start to seriously believe you ARE a god or some sort of entity because of how powerful you are, and therefore you do actually begin to gain powers, or just luck that makes it seem like you have that power. Eventually once you have enough faith, you would be able to counter magic, or nerf it heavily, just simply with faith energy. Eventually the god's magic wouldn't exist, and all they would be is a megabeast to you.
Belief would keep you up in the heavens. This would provide a practical explanation for megabeasts and forgotten beasts- Gods of old who simply gave up due to the fact people stopped believing in them. Maybe they came down to make it known that they do exist. Maybe they came down to be worshiped. So even if you rose up to the god level, people could 'forget' you.
Not necessary right now, not perfect in any way, but I think gods do need more character, adventures do need more character, and this would be my way of implementing it.