What do we know about the Camoran Usurper? He was Mankar's father, from what I understand.
This is a good story about that: http://www.imperial-library.info/obbooks/refugees.shtml
I think Ted Peterson was the author.
Another story: http://www.imperial-library.info/dfbooks/b041_usurper.shtml
Also from the Imperial Library:
"3E 249: The Camoran Usurper leads an army of daedra and undead on a rampage through Valenwood, conquering kingdom after kingdom."
Source: A Brief History of the Empire, The Fall of the Usurper."
"Haymon, the Camoran Usurper, conquers eastern Valenwood. Haymon's claim to the Camoran throne and his very origins are still debated by historical scholars. The most persistent legend is that he was the progeny of a Breton woman and the daedra Molag Bal. Certainly his army was largely supernatural, but so was that of his archfoe, the Baron of Dwynnen." From http://www.imperial-library.info/history/3.shtml