I put it as "concubine" because MC's mother (when he transmigrated) was actually a lowly maid who accidentally got pregnant because the person she works for husband ended up doing it with her when he was drunk.

MC's family (besides his mom) kicks him and his mom out the house and sending them little to no amount of food each month just because his mother has a really low status. The elders at his family try to let him remember that he is still a member of their family so that he has to help them in the future after he got 1st place during the exam competition. Basically just an example of when you are useful, people will play along or let you remember who you are/were, but once they are done using you, they will throw you away.

MC's friends and the emperor. ML doesn't appear until chapter 15.

Both MC and ML do get married to women (so basically other people) and have children of their own. It's realistic for the era for men to get married (pressure from family played a big role in this story for MC, I feel) but also realistic because ML needs an heir. Fret not, they don't have a lot of children. But sometimes in this kind of plot, it makes me almost sad for the women in the plot. But alas, such was the era. Also a bit annoying but the marriage thing esp for MC spanned a long while. So the fact that his marriage to someone else keeps coming up in the story kind of spoiled it a little for me.

he had more familial love for ML than romantic love. I hope it's because I didn't read well so I will definitely check back again with the translation. There's a "love rival", this guy who saved MC and MC kind of saved him (?) who becomes like his bodyguard. I just feel that if that rival had initiated intimacy (that MC might not even reject, he did joke about marrying him had he been a girl, if I recall, he says that to another friend of his who may or may not have a crush on him too) with MC before ML did, HE would have been the ML. Like MC loves ML for sure but it almost feels like he's going on ML's whim because of the deep familial love. Also, this book is so slow burn, by chapter 50 I think ML is still like 8 or 10?

is an age gap between the MC and the ML as the MC was already on his way to take the imperial exam when he met the ML who is still a child.