And where is Erebus? In this galaxy? On another universe?
I'd say another multiverse.
And did the different races form just like different races formed on Earth: evolution?
Yeah, but not through natural selection. Closeness to a god greatly effects how different peoples diverge.
Dagda proposed making Erebus of equal parts of all the elements and making man as a creature possessing equal parts of every element and also a divine spark, so that they would have a true form of free will, greater than that of the god's whose personalities are dominated by their own precept. Creating a new divine spark is something only The One could do, so they could only give mankind free will by having man be descendant of the gods. One god would need to give up his power in order to father the new race. Only Nemed, the God of Life, was willing to do this. He gave his precept to Arawn, God of Death. Apparently the gods together made Gabella as a mate who was his equal, but I don't think they really had this power. She clearly has a divine spark, as she is a very powerful sorceress. I think that the man Nemed and Gabella were formed from two halves of the God of Life. Gabella refused to submit to Nemed, and bore him no children. If we had been descended from both Nemed and Gabella we would be true immortals, in both spirit and body. The gods fashioned a new mate for Nemed out of the raw elements, but she was mortal and without a soul. Their children inherited her mortality of body and his immortality of soul. The first generations however were still extremely long lived.
The ancestors of the Elves lived with and were close to Sucellus in the Age of Dragons, and were changed into more graceful, longer living (than other races, not necessarily than their mutual ancestors) creatures. Aifons similarly were close to Danalin and gained the ability to breathe both air and water. The righteous crusaders of the Bannor in Age of Magic were very close to Bhall, so those who were not dragged into hell with her physically manifested her corruption and became bloodthirsty Orks.
I tend to think it would fit better for the Dwarves to be humans who were close to Kilmorph, but officially we are still to go by the story of Keldon Ki. He was an extremely skilled artists who was commissioned to carve a statue of an arrogant king in the Age of Magic (who would presumably be Kyorlin), but was imprisoned when his completed statue clearly looked as arrogant and corrupt as the real king was. He grew old in prison and very lonely, so he fashioned little statues to keep him company. When he was close to death Kilmorph appeared and offered him one wish. He turned down youth or rebirth, instead asking only for companionship in his last hours, so she brought the statues to life. These were the first dwarves, who were immortal. Each generation had a markedly shorter life than the last.
Where is the hell? Below the Underhome? (Which, if I'm correct, is due below the crust of Erebus?)
Hell would consist of 6 other planes (plus the connections between them, and possibly numerous other secret planes that only Ceridwen knows about) which could probably be considered seperate universes, but which are all connected. One generally heads down deeper as one goes to lower levels of hell, but I don't think that it would actually be able to go from plane to plain without going through specific portals.
Why did the dwarves not like Erebus and resort to the Underhome?
Humans drove them to isolationism. The Dwarves were once honest, hard working, and very trusting, but their dealings with humans made them distrust us greatly. Humans liked using magic to conjure illusions of good that they would trade for high quality dwarven products, thus dispoiling the dwarves of their wealth. When this didn't work, they would often overpower the dwarves and steal from them. The ancestors of the Khazad got fed up with this, and retreated completely into their tunnels. It is said that they didn't even notice the Age of Winter for at least a generation since they rarely went outside anyway. They have however now run low of resources and room, so they have been pretty much forced to explore the outside world again.
According to their creation myth, the Underhome would have been founded by the tunnels the first dwarves made to get out of the prison where they had lived with Keldon Ki in his last days, and never completely left it.
The ancestors of the Luchuirp however had left the underhome completely and forgotten how to dig. They were very urbanized surface dwellers who were unaccustomed to any work but skillfully crafting golems. The Luchuirp tribe itself had to be taught to dig again by Kilmorph herself to survive the Age of Ice.
During the Age of Ice, all races (apart from the Illians and Doveillo) withdrew to living in caves for protection from the cold.
And why did Cassiel abondon his angelness to become godless and live on Erebus?
While the Compact was Cassiel's idea, he despised its final draft and could not bring himself to accept it. He wanted to end the war for the sake of humanity, but all this did was turn humanity into pawns in a more subtle war, and established that gods had the right to own the souls of their followers and could do whatever they want with them. It did offer some protections to humanity, but was far from absolute. Demons could not directly hurt the innocent, but they could empower the corrupt to do for for them. The gods could not personally enter Creation, but they could send powerful angels to intervene, although in a limited capacity. Cernunnos spent all of the Age of Ice with the Ljosalfar, but he was there to guide them and not perform miracles. Technically there wouldn't be anything illegal about Sabathiel guiding the Bannor from within Erebus, but as the archangel of law he is bound to the strictest possible interpretation.
Cassiel stormed out of the meeting at the Seven Pines in disgust, as did Basium but for very different reasons. They both chose to fall (the right of an angel to fall was also established in the compact), loosing their god's ara and protection, becoming essentially mortals. I don't think they age and they are still quite strong, but they can be killed by the same sort of wounds that would kill a man.
If there was a Compact, why did Basium and Hyborem come without a fight?
Basium broke the compact before it was signed, and ignores it completely. Since he fell and is not being helped by his god (Arawn), it doesn't really matter. Hyborem is treading a very fine line over what is allowed. He hasn't broken the letter of the law, but has certainly violated the spirit. He and his demons are allowed to act in creation when invited by mortals. Thematically, they probably shouldn't be able to directly invade the lands of the good, or at least should be far weaker there. Agares has helped Hyborem, but is very careful not to do enough to attract suspicion of the other gods. He would not risk sending Hyborem back a third time, which is why Hyborem doesn't regain immortality.
If there's proof that the gods exist, why does Cassiel not want to worship one?
Cassiel does not believe that The One wants worship. He associates worship (including both the desire to worship and to be worshiped) as part of Agares' taint, and refuses to believe that The One would have traits anything like this. (I do think that worship is part of the sphere of hope, but he neglects that the sphere itself was originally good and that The One accepted worship for ages before Agares' fall.) He thinks that the fact that The One withdrew from Creation means that he does not want humanity to know about him, because it could be deleterious towards their enlightenment. The fact that none of the good gods (even Sirona or Lugus) have ever told their followers about The One may indicate that this is right. The One never told them to tell us about him (he also never ordered them to fight evil), only to protect us and guide us towards enlightenment. Cassiel thinks that the gods/angels should follow his example and leave mankind completely alone.
it is worth noting that Cassiel was not created until after The One closed the true heaven off from the gods, so his knowledge of The One is entirely second hand and possibly wrong.
And why do Gods kill the Grigori for their sport?
???
Who ever said they do?
Kael Cassiel (why have I been witting the wrong names so much in the past month or two?) does think that the gods have horribly abused humanity in general, but not specifically him people. Generally good and evil are too busy fighting each other to mess with them.
Are all Octopus Overlord followers insane?
Isn't everyone really?
Most of those who follow the Overlords are probably no less sane than anyone else. Well, actually the "followers" probably are rather insane, as those who know anything about the Overlords know that they never agree with each other on anything and that following one overlord would just annoy another. Anyone who actually seeks the will of the overlords will go mad. However, in their madness they are quite useful, as their nightmares do show the future. The more powerful of those who believe in the Overlords seek to exploit them and the madness of lesser men.
What mental condition do they have? Skitsophrenia (if that's spelled right)? And how do they get it?
I don't know, it probably depends on the individual. Lying face down in the water until you receive a vision and hear the whispers of these abominations of the deep are probably involved in driving them to their various forms of mental illness.
Are the Doviello half-wolf?
NO. They are quite human, but inhumane. Charadon patterned his society on the wolf pack and they venerate the beast, but they are completely human. They do claim descent from an orphan raised by wolves though, not unlike the story of Romulus and Remus.
If the Mercurians are so war-crazy and powerful, how are they good?
Good in FfH means anti-evil. The Mercurians are the most devoted of all to fighting demons.
Why didn't they just form Patria again instead of breaking up? Was Patria human until the races evolved?
Patria was the first empire of man, which united every human people under one King, Kyorlin. (The ancestors of the Lanun and probably a few other peoples though were probably more like vassals of the empire than subjects though.) The Elves and Aifons were seperate societies, who at first were friendly with Patria but never under its control. The Dwarves weren't created until the empire started becoming corrupt (if their story of their origins is true). After Kyorlin's wife Eve cheated on him with another man, he tried to commit suicide. Ceridwen stopped him and promised him eternal youth (and thus practical immortality) and made Eve be eternally reincarnated each generation, so they could be together without her flesh being tainted by another man. She also taught Kyorlin to use magic, and made the already powerful kind the strongest sorcerer in history. In exchange, he had to worship Ceridwen. Kyorlin became an extremely corrupt despot, and taught his students to be just as wicked. The people of Patria suffered horribly at the hands of these archmages, who were all evil at this time (well, I think at least a couple were pretty neutral, or else just changed latter on). The reborn Eve found Kyorlin repulsive (I think he probably raped her in at least one reincarnation), and he eventually did too. He eventually repented and led a rebellion against...himself. Well, basically he tried to change the laws back to how they used to be and make his nation just again, but his students would not stand for that. They (I'm thinking under the leadership of Perpentach) kept control of the army and all the real power, but he led a small group of rebels, which eventually grew into a revolution. There was a massive civil war which eventually stabilized into several different nations, which then were crushed by the Age of Ice.
Did The One create himself?
We don't know a lot about The One, but creating oneself doesn't make a lot of sense. Presumably, he has always been and always will be. Time did not exist until he created the orb of temperance.
Why did I spend time witting this instead of my papers and lab reports?