Thousand Incarnations of the Supreme One, by Huan Yi's own admission, the number one incarnation skill in existence. By relying on that unique skill, Tianye could produce 1,000 avatars that each reached the grandmaster stage of one principle in existence—no matter who or where said principle had been created.
The true brilliance of that skill came from the fact that Tianye didn't actually need to cultivate those principles to that level. Instead, she relied on her Power of Infinity and the unique Power of Duality that she possessed to hijack those principles and wield them through her avatars.