If I remember right then this humin is the real humin like he thinks he is in novel called 'silence' but everything that happened in that silence as our humin thinks happened to novel humin actually did happened to our humin. His real world that he thinks he'll go back to doesn't exist it was created in his head as a trauma response. Seme is the one who's back from future to fix things. Humins brain is probably blocking those memories as trauma response thus creating that other world where he has a normal life and seme was his best friend. If you read recent chapters with what I said you'll start to understand. There was never a novel 'silence' it all did happen to our humin but he thinks it's not real and his normal world is real where he and seme are best frnds. I think when seme jumped back in past he himself forgot it all which explains his behavior in the beginning but j think when they slept together the very first time his memories came back n he remembered he turned the time back. Humin thinking that Everything is going differently than the 'novel' ( he doesn't know all that actually really happened) could be the result of the butterfly effect. He is seeing those past memories in dreams and he thinks he is remembering novel scenes which is actually a sign that his memories might be returning that's why we see seme saying he shouldn't remember n blah cuz he won't accept seme if he remembers what he did to humin. Am not sure if Seme knows humin killed himself after seme was killed so he never knew how much humin did loved him despite how cruel he was to humin. That's why he doesn't want humin to gain his memories. I only found the spoiler of the novel actually being reality and humin forgetting it. But it starts to make sense from there. I hope am right.
Season one did not disappoint. Tho I ended up reading some spoilers in the very beginning it still kept me hooked. Can't wait for season 2