Concerning the genetic make up of Mordred, even if he is 80% human (and that may not be the case since it appears genetic engineering is involved. Who knows how the Frankenstein wannabees changed the proportions?) I think that 20% demonic DNA goes a long way. And besides, I think the effect is as much spiritual as physical. I've often wondered if Susannah actually contributed any DNA. I wonder if Mordred is just a son of two fathers... I know that's naturally impossible but Mordred's conception was far from natural.