I expect the reaction would have been very different from the townspeople if Raki had any yoma parts in him. They were saying things like, "He's just a man, and he defeated yoma without being a Claymore. OMGZ!" and the yoma itself obviously sensed no Yoki out of him with the line, "It's as if he is a Claymore."

Not to mention that Raki used the little girl to point out the yoma. If he had any Yoki from anything, he'd have been able to tell on his own.

Isely just trained the hell out of him, and Raki developed armor and sword fighting methods from that training that would allow him to win every time.