Forgot to save the raws I was reading. It's not on NU, I really hope someone knows this. Involves spoilers for the first couple of chapters. In the first life, MC was the Young Patriarch of a powerful family in the top spiritual world. He was disabled due to birth defects, and was frozen as an embryo for hundreds of years before he was born. He couldn't walk, but he had high attainments in formation and comprehension. The elders of his family were killed after being betrayed by their friends. They wanted to snatch some treasure born in MC's family. But MC arranged a killing formation and he and his clansmen died together with their enemies. So when he died, the treasure chose him and he was reborn to a lower world thousand years ago. About ML: In the first life, ML was MC's giant guardian puppet. He had no consciousness, only a remnant soul. He was a cultivator who used the blood of his enemies to cultivate. He was a righteous person and only killed evil cultivators. After taking his revenge, he decided to become the guardian puppet of infant MC. After MC 's rebirth, ML was the Young City Lord of the place where MC was reborn to. This was a mortal world with only martial artists. ML's dad was killed by a Qi Refining Cultivator and MC rescues ML. ML also decides to cultivate so that he can avenge his father. I remember MC & ML being very young, around their early teens.
I haven't read it yet because it's not complete....but I think its 混元修真录[重生] the same author as I have medicine, and transmigration's cultivator, one of the author's long novel...