Well, this thread is super dead, but I might as well go for it. Can anyone confirm if I got the story right?
The werewolf looking god is an ancient being that's been in existence forever. At some point, some archeologiest (Hakauro) finds it and gets killed by his partner. As he is dying, he becomes fused with the mask and becomes the god's vessel. He remains dormant or frozen underground.
Sometime later, Earth has been devastated by nuclear war or environmental collapse and became uninhabitable. Humanity retreats underground. They discover Hakauro (Iceman) and do some research on him. The fruits of this research is the furry race they create who can survive on the surface. At some point, one of the researchers lets iceman and some furries escape to the surface because of his guilty conscience. Iceman and furries live peacefully on the surface for a time. Iceman bangs the one that looks like Eruru (#3500 or whatever) and has a kid. Undergrond humans send the mecha dudes to capture him again. They kill the wife and kid and experiment on them. Iceman loses his shit and the god is manifested. He destroys everything and turns the researchers into slimes by granting their "wish." This god seems to have a good and evil side. The good side implores someone to stop him and Kamyu's original self (#68) answers him. She couldn't kill him, so she seals him, but the god's 2 halves are separated. I think Iceman keeps the good side within him.
For a long time, there is a cycle as one of the gods awaken, do some stuff, then go back to sleep. But not at the same time. For how long did this go on? I'm not certain, but it has to be hundreds, if not thousands, of years. The surface is populated and they have lost all knowledge of the past.
At some point, Diy, the philosopher, finds and awakens the evil side. He becomes fused with him. I suppose it was Hakauro/good side's "turn" to roam the world, but Diy awakens the evil side early. I believe this lead to a clash between the two sides and that was the cause of the earthquake. Hakauro loses the fight or is at least mutually hurt.
Meanwhile, Aruru is hurt during the earthquake and Eruru calls for help. The Hakauro in god form answers this and binds her to him (to heal him up) in exchange for saving Aruru. He reverts back to human form and loses his memories. That is the start of the game. Everything is more of less straightforward from there.
Now there are a few things still confusing me. Kuuya said that whatever god the angel people worshiped was a false god. From what I can guess, I believe this Bunny people are worshippers of the evil side, who later fuses with Diy. That leaves me wondering what the extent of the angel people's knowledge was. How much do they know of the cycle and Hakauro? What contract did Uroity make? With who? Why couldn't she tell Hakauro anything?
Did the angel people worship the full god we see when the two halves are fused? Or did they worship the "good" side that is dormant in Hakauro? It seemed like they had some idea on Kamyu's dormant identity. This personality (#68 Mitsuko or whatever her name was) must reincarnate as one of the angels every generation or something.
What was Genjimaru's contract with Diy (evil side)? What actually was Diy's plan anyways? He just stirring up trouble for fun?
Are we sure there isn't some reincarnation stuff going on with Eruru? Why does she look and sound like the girl Iceman escapes with? Why does Eruru have that circular key thing to open the door to the lab? Iceman gives that key to his baby girl, but she is captured and "dissected." Besides, there has to be a huge gap in time between Iceman's escape from the lab and the events of the game where Hakauro meets Eruru. I was thinking that maybe the baby somehow grows up to be Eruru and it's actually some kinda incest lol, but that interpretation just doesn't fit the timeline.