Oh, so the MC saved the ML while he was still stuck as a snake and couldn’t transform yet. His dad tells him to show off his archery skills, and he ends up taking out the eagle that was about to hunt the snake. Then the author draws the snake straight-up blushing at the MC, and the MC just goes “aw, cute,” lol. (MC was kinda already aware the snake was a demon since it was hanging out in the snow like that.)

There are 13 chapters in this manhua.
Yulang (ML) gives the MC his core, and the MC turns around and offers it to the emperor to eat (emperor was sick and the core was supposedly a cure). But Yulang was actually aware of everything the whole time, giving his core to the emperor was specifically to protect him from the heavenly tribulations. So the MC ended up helping Yulang while thinking he was betraying him. Yulang escaped the tribulations and became an immortal being.
From what I gathered, Yulang then kills the emperor from the inside (the core was essentially him, so once the emperor ate it, Yulang was inside his body and just… appeared from within and took him out). Helping kill the emperor means the execution of nine generations of your family, and we see the MC in his first life completely breaking down over it. It’s implied he grew up under constant pressure from everyone around him, his own father even said he didn’t need a useless person in the family, even if it was his own kid. Then there’s a bunch of convoluted text about how he was just used as a chess piece by multiple people (his father, mother, the emperor, Yulang, etc.).
The present MC wakes up inside a casket and starts screaming, he probably dies right there. The ending shows his next reincarnation walking into the house/mansion from the first chapter (where the ML lives), asking if “he” is the owner (ML isn't shown) and saying he got lost in the woods. Lmao.