It's a little poorly worded, but they DO line up.
Nasus' lore speaks of the world as a hole, describing two seperate factions of the same race that inhabit it and then going onto jump into the battle between the brothers. Also keep in mind that this is skewed by his understanding of the events. He saw Renekton as merely one of the "We are Gods" faction coming to kill him while he was actually just twisted by his exposure to evil while doing his job.
It could definately use a little refinement, but if you take a step back and don't look at it too closely it makes sense.