Like most players of FfH I'd wager, I'm generally a lurker. But that lurking has been happening since Fall from Heaven 1, and I've been a big fan of it from the beginning. Think the original campaign started somewhere in Fire.
Obviously I love the lore, too. And judging by the creation of a guide, I'm also far from the only one that combined my love of FfH with DMing.
Who knows how many people out there are siphoning the powers of Kael for campaigns in total secrecy? Could be a cult following of thousands exploring Erebus every weekend.
Edit:
Also, now that I've actually installed a program capable of reading the guide on this new computer, I'll definately say that I wish I had this thing back when I was DMing my campaign. Just having all that history in easily readable form would have saved me ages of work in having to type it and write it up for myself. Not that I would have given that all to my players, mind. I made a big point of making sure history and knowledge was pretty frayed after the Age of Ice. It was only in the middle of the campaign, when they found the remains of a temple to Oghma, that they even discovered that the gods they made offerings and such to their whole life were completely fictitious. Well, except for Esus, but that goes back to the the whole plot of Esus' relic slowly corrupting knowledge of the other angels.
I had started a sequel to the campaign above in 4e, set decades later, that didn't get far, due to various reasons of people's lives getting in the way of the game. I'll try to remember what I did to Erebusify it.
-I know that the Sidar in my game weren't a race. They were essentially Fae-pact warlocks, slightly reflavored to make their abilities more shadowy. The RP results were the same though, losing emotions and becoming ageless.
-Dragonborn were the results of Cult of the Dragon experiments. And in my games they were also the result of 'contamination' with the blood of one of Ceridwen's dragons that was awakened by the CotD, and slain by the players (with much help). People that lived near where the monolithic creature died started to be born.. strange. The same is true of those that lived in the same city as the Bone Palace, which was made from its remains.
-Dwarves were dwarves. Luichirp were also dwarves, but were wiped out in the part of the world my campaigns were concerned with before the end of the Age of Ice. Probably still kicking elsewhere.
-Eladrin I had originally thought to make Sidar, but for some reason I changed my mind, so they were out for that particular game.
-Elves were both Ljosalfar and Svartalfar.
-Halflings used to be humans (Well, that's true of every race I can think of in Erebus). In my campaign, many of the angels had small groups of favored worshippers, like Bhall's people who became orcs, who they placed some kind of blessing upon. A small tribe was favored by Nantosuelta, for their outlook on life. She gave them two objects, the twin Hearts of Faith, infused with the traits she admired in them. The tribe lived a charmed existance in the glow of those artifacts, even through the Age of Ice. As long as they trusted in ability, luck and the good will of their god and those around them, that faith was made to prove justified. At some point near the end of the Age of Ice, by which time they were thoroughly infused with the powers of the Hearts, one of them was stolen. Nantosuelta's people diminished, by the loss, both physically and in their blessings. Still though, they're gifted with uncanny luck and trust that in the end, things will work out. (What a naive view in Erebus, huh?)
-Humans and Half-elves were humans and half-elves. Crazy, no?
-Tieflings were a mix of those who legitimately had lesser angelic blood in their veins, children who were in the womb when their mothers were touched by great evil, and people corrupted by delving into the most depraved demonology. The latter catagory made sure that the whole species was rather unpopular around town.
-Warforged were rare pre-Ice Luichirp golems imbued with at least a simulation of intelligence. The question of if they had real souls or thoughts is a constant debate.