>>11100069Presumably, they're cybernetically augmented, organic humanoids. However, as far as we know, they're born with the joints, so...maybe nanomachines?
>can polynians grow seamless joints similar to humans without the grey round balls?They can grow human skin in general. The protagonist of the VN (pic related) looks exactly like a normal human boy, but his biological mother is a normal-looking Polynian. At the time of the story, pretty much everyone on the planet is part Polynian, part human, even the other Polys that we see like Yume, Iana, Machaon, and so on. Clover and Shamrock (Purple and pink haired versions - the blonde ones are modern siblings who are descended from them and share their names) were the only two 'pure' Polys in the series, being members of the initial wave that arrived on Earth during the war (and Clover getting knocked up is what canonically brought peace between the two species).