User blog comment:CoolJazzman/Uryu "Last Living Quincy"?/@comment-5657895-20130630062430

I was thinking that the Stern Ritter and the Vandenreich in general aren't real Quincies, rather they are people given Quincy powers or perhaps they are reishi creations of Yhwach. That would effectively make Uryu the only Quincy born naturally. Worth considering.

Concerning Ryuken, he does seem to have turned his back on the Quincy way of life, so maybe Yhwach as figuratively disowned him.