User blog comment:Schiffy/BG9: Man, Machine, or Something Else Entirely?/@comment-5551986-20130929133155

Stern Ritter have abilities related to their letter which ties in with their epithet. So I'd assume "K" is what has made him into a robot thing. Letter K - The Kinematic = The relationship between the motion of the endpoint of a robot and the motion of the joints, so it revolves around that. He said he has never breathed, so I'd assume he was created by either Yhwach or another Stern Ritter. But he could have been saying that simply to lower Sui-Fengs morale.