Pu Yao is a Sky Yao and survivor of the One Thousand Year War that lives in the consciousness of Zuo Mo. He first appears as a ling plant disease, then a dandelion seed before taking up his human-like form inside Zuo Mo. Pu Yao is has raven black hair, a red gem in each ear, and a pair of red eyes only one being displayed while the other hides behind his hair.
Pu Yao initially seems to be more of a menace to Zuo Mo than a teacher. Supplying him with broken, flawed or incomplete skills that could potentially cripple him or at the very least leave him broke with little observable benefit. Despite his proud and often mocking words towards Zuo Mo, he eventually becomes both a powerful teacher and strong pillar of support from the shadows for the faction he created.
He was able to manifest outside Zuo Mo's body with the help of the Ghost Mist Child.
Pu was an extremely talented Yao who rose to prominence before the One Thousand Year War. He was the vice leader of the troop composed of most of the Sky Yao and Mo fighting in the war. He was also the second strongest in the troop, only losing to his daren, the Leader. The leader was a female Mo, who Pu seemed to have a deep connection to. She was also the previous owner of Wei, or rather the suit of armor Wei is the spirit of.
The armor also seems to have a dark secret of some sorts, with Pu saying that it ruined her life and he wouldn't let it ruin his dispciple's (Zou Mo) life too.
Before the final battle in which most of his companions were slaughtered, they all shared their secret arts, vowing that if one of them made it out alive, they would pass the arts on to their descendants. Pu seems to value this promise a lot, passing on several arts to Zou Mo, to pass them onto his friends' descendants.
Pu was a Sky Yao before he was greatly weakened and he cultivated flames. When he first appeared in Zou Mo's consciousness, he appeared amidst a sea of dark red flames. These flames don't seem to be special flames unlike the ones Zou Mo could control and use in forging, but they contained an incredible strength regardless. Unfortunately, Pu's strength declined after he was sealed for 3000 years, and using these flames is greatly taxing on his spirit.
Other than his great strength, Pu has an incredibly vast amount of knowledge about all three of the cultivation paths, Yao, Mo, and Xiuzhe, though most of his knowledge is about Yao. But even so, he was able to modify mo skills using yao arts like he modified [Hardship Guard] using the Great Day Mo Physique. His teacher also passed a secret art onto him, the Archaic Wasteland Sacrificial Art, which is an art that comes from little yao arts. Unfortunately for Pu, he wasn't able to practice the art despite his teacher not hiding anything from him, and only taught it to Zou Mo for fun. He wasn't expecting Zou Mo to be able to actually cast it.
His terrifying ability to create simulations from the torturous sea of spells and yao arts helped him reconstruct shen methodology for Zuo Mo. Shen power was much more complex than yao arts and the work to reconstruct the method was unprecedentedly vast and complex.