We have not been given any concrete information except that normally when a deity dies down in mortal world, they go to heaven and when they die in the dungeon, they are devoured by it. This might tie in with the mysteries of the dungeon or something.

I could be misremembering some things, but I do know there are technically two forms of "deaths" for the gods. There are a couple instances of actual deaths, where the gods die and are then reincarnated as another being, but most of the "deaths" we see are actually just the gods being injured enough that there Arcanum is activated, thus banishing them back to heaven (basically all the ones with the giant beam of light).

I don't recall if its ever been said what happens if a god is killed in the dungeon. I remember Thanatos specifically "killing" himself in Knossos to help Loki Familia escape, but I don't know if that would count as part of the dungeon or not.

It was stated in the astrea record that the dungeon would swallow the god in question, which is why it was dangerous for astrea and ereberus to go down there.

This setup of a Dungeon being dangerous to Gods is familiar to me.

It reminds me of Greek Mythology to Tartarus there is a specific section there that Gods should not enter.

@Emiya4578 Was not aware of this area of Greek Mythology. But what I do know is in instances like this the Dungeon acts like an organism utilising its immune system to its fullest to remove a potentially dangerous foreign object.

Sorry for the wait! Been one hectic week at work (and still learning the ropes - getting busy!). @Kevhunt06 - you're absolutely right about Τάρταρος. The titans were sent there and so were several deities either sent there or threatened to be sent there. As for the death of the Greek gods, that was near impossible. Only god that I know that supposedly "died" was Πάν (Pan). According to the Greek historian, Plutarch, Pan was the only one to die (and the story behind that is kind of vague and maybe not reliable at all). Even if they were "killed" - at most that meant that they were "changed", such as Οὐρανός (Ouranos/Uranus) - castrated & torn to pieces (depending on the account), parts of him became the sea foam and parts of a mountain range, and his deity was confined to "the heavens" (the sky - "the first heavens"). Even the titan god Atlas - changed to stone, but considered a living mountain afterwards that still held up the sky. So, if you can't kill them - imprison them... thus one of the purposes of Tartarus. Hope this is helpful. Oh - and regarding the part of the Astrea Record - I do remember that was the case, the warning that the Dungeon would use their divine energy for itself, not to be released. I don't recall any "reincarnations" of any Greek/Roman deities. Those below full god status could be killed (although maybe difficult, too), off-hand can't think of reincarnations of them either.