I dunno, seeing as his name is the Progenitor, it would probably follow that the Demis were his children.
The problem with that theory is
1. If you read the post made by Neilo which tells the story which can also be found in the opening of the game; all the progenitor's ken were slain.
2. Tb, Occulus, and Sedna's parents are in their story and in Tb story his step father killed his real father and mother, and than tried to kill him but only succeeded in killing his friends and girlfriend. Which made TB kill everyone in the country I think also Tb his human gone lich.
Occulus killed his own father.
Sedna left her parents never to be seen again, oh and sedna is human.
DA and Ub were both brought into the worth through sorcerery so ya they were not even born.
From what I got from rooks story he was human. This means he did not even become a demigod until after his death... which I kind of think Da was the assassin who killed him.
Reg and ere stories really say nothing about their parents so ya.
Queen of thorns is a fairy...enough said.
Oak...Somebody has alot of explaining to do on this one.
Firstly for they to even be his kids they would already be gods and not have to fight for their fathers position, because in the to of most ancient societies the eldest brother inherited what was once their fathers. Secondly the winner wont even become a god they would actually become a demigod. Which if you read their stories than you can figure out none of them are even part god yet, and the only thing godly about these character is the fact they all have a limited immortality (Meaning they all can't be killed through normal means...or mortal hands) it may seem from some of their stories. Demi means half so for them to be his children he would have had to sleep with about 3 mortal woman, 2 books, one suit of armor, a angel it may seem, a female vampire, and a female minotaur.
So how do you see them as his children let alone even half god already? They are literally fighting to become a half god, but they will take the place of a god; it doesn't change the part of them that isn't god thus making them demigods only after the winner stands above the rest. Which will be queen of thorns.