As for the ML, he's the father of the buns. Who rapped the original owner, although it was because the ML was drugged. But he still had to work hard to gain the trust of the MC.
The MC doesn't appear much in the first forty or fifty chapters, well he's bedridden, and lost his memories. (it's cute that he thought he and the original owner was a couple and wanted to get back together. Well the MC is... black belly, it took him a while to accept the ML.)