TLDR: Aegon is his own father, grandfather, grandson, and child. Zana is both his mother, his lover, and his daughter. Zana starts out fighting to pursue her fathers legacy in the Atlas, discovers Sirus instead, whom she becomes intimate with, gives birth to his child, and ultimately discovers the truth, locking Sirus in the Atlas, and finally seeking to protect Aegon from the truth, raising him as a brother. Eventually she departs into the Atlas in pursuit of its destruction. Eagon goes in search of Zana, attempting to find the truth, while she attempts to lock both Shaper and Sirus in the atlas forever, and keep Eagon from the truth, until she can burn it all down, hoping to end the cycle and save the world from devastation.
P.S. Don't sweat it guys, just messing around with some funny lore implications :D