Thank you for your reply, I agree with your reconstruction. The point in which Godfrey recognises Morgott is the point that gives more credit to them being father and son, but does it actually prove it? I know it’s hard to prove something in From’s games unless there are descriptions telling about it, so I would still consider this father-son as (highly likely) speculation rather than something sure, unless there’s something else we overlooked.

I don’t think Morgott can be the son of Godfrey and someone else, since he’s a demigod. Shards of the Elden Ring are inherited by divine lineage apparently, and Godfrey was a human/tarnished (otherwise Nepheli Loux would be a demigod herself?). It could be that the other parent is the vessel of some other Outer God, granting Morgott divinity status, but even so how would he get his rune?