So long as the Eclipse ap-
proaches them on legitimate business of some kind,
shades, spirits, the demon princes of Hell, and the Fair
Folk may not attack the Eclipse or her companions
without just cause, and such creatures must observe the
local rules of hospitality.
"You want refuge but do not offer to swear oaths of surrender of the same potency as the ones you forced on us? I have considered your offer and I reject it. These negotiations are over. You will leave my lands as fast as possible and will not linger or divert from the quickest path. You are not welcome here, and should you stay, we will annihilate your army of invaders you bring with you. Leave."
The Eclipse diplomatic immunity is in fact very narrow. It only applies when they're on legitimate business. Just cause includes "staying once you have been told to leave and the business is concluded". It forces them to not attack immediately, yes, but it doesn't actually stop them from hearing your proposal and going "Fuck no. Get off my land, or I'll consider you an invader" - which as a statement is fully compliant with the Eclipse protections. It is not a power which lets you walk around on someone else's territory unmolested. It ensures you can get to them safely to make your proposition, and won't be attacked for as long as negotiations are ongoing.
Nothing stops them from declaring negotiations over and allowing whatever customary time is permitted for you to get off their lands before attacking. Because once they've rejected your offer and refused to continue on with negotiations, you no longer have legitimate business.
A thought based on the "Gods did it for the games, not humanity" line: Would both groups try to sabotage the other's efforts to gaining entry? The Yozis hate them both oh so much, but might they accept one group on a platter to allow the other? I'm sure they'd love to watch the exalted fighting the gods for the privilege to enter Hell.
Oh, there's a good chance that the Yozis would offer humanity serfdom and the Exalted citizen status in return for oaths of servitude and non-aggression if they were just to hand the gods over to them. All they need to do is admit that they were wrong and bow to their creators once more. After all, humans are just prayer cattle. They don't really matter. And the Exalted can be bound by oaths. Their torture can be a slower, much more gradual thing, as the Yozis leave all humans like the Men of Malfeas. The beauties of the Demon City will break their hearts and they will slowly be shown and come to know that they were wrong to rebel. The Third Circles know that the Exalted can be swayed and one day they may trick every last one into akumahood, one by gradual one. Then they will serve them instead.
The Yozis are have time. They can play a long game, once they have their oaths. Once the humans have sworn the same oaths that the other Primordial races had, and so cannot harm the Yozis.
Ah, but the gods? The gods are the ones who planned it. The gods are the ones who stole Creation. The gods are the ones who made the Exaltations. And the gods are immortal - every human and Exalt who warred against them originally is dead. The gods include ones among their number who are personally responsible for what was done to them.
There will be no flicker of mercy for the gods. Not even when they beg to die. They showed none and will receive none.