We have a bit of a contradiction here. which makes for the greater sorceror: a pure man or someone with demonic ancestry?Hi Tu!
Which,echo's Orastes from HotD,...
THotD, Chapter 20: Out of the Dust Shall Acheron Arise
"When we employed the Heart of Ahriman to bring a dead man back to life," Orastes said abruptly, "we did not weigh the consequences of tampering in the black dust of the past. The fault is mine, and the sin. We thought only of our four ambitions, forgetting what ambitions this man might himself have. And we have loosed a demon upon the earth, a fiend inexplicable to common humanity. I have plumbed deep in evil, but there is a limit to which I, or any man of my race and age, can go. My ancestors were clean men, without any demoniacal taint; it is only I who have sunk into the pits, and I can sin only to the extent of my personal individuality. Out behind Xaltotun lie a thousand centuries of black magic and diabolism, an ancient tradition of evil. He is beyond our conception not only because he is a wizard himself, but also because he is the son of a race of wizards".
It may actually be that pure-blooded men are the best genetic sorcerors as both Khemsa and the Master of Yimsha are human:from The Bloody Crown of Conan the Cimmerian, "The People of the Black Circle" pg 56
"You are a devil," she sobbed.
"Not I!" he laughed. "I was born on this planet, long ago. Once I was a common man, nor have I lost all human attributes in the numberless eons of my adept-ship. A human steeped in the black arts is greater than a devil. I am of human origin, but I rule demons."