- Enmu promised Rui that when he returned from his mission they would go to eat at their favorite restaurant, his treat, but since he never came back, Rui never went back to that restaurant again
- Nakime's Kasugai crow was very old and had a very bad memory but she still never forgot Nakime or anything about her
- since Dōma's death, snow became Inosuke, Zenitsu, the Shabana and the snowflake trio (Naho, Kiyo and Sumi) favorite thing
- Hiroko sometimes thinks that Kyogai is Nakime
- Dōma always sent letters to his children when he finished a mission, so when the news broke that the war was over but there was no letter and he showed no signs of returning, everyone assumed the worst
- the snowflake trio sometimes read Dōma's letters as if it were the first time
- when Hakuji died due to the demon slayer mark, he felt slightly happy for being reunited with the others, to finally be able to apologize, tell Dōma that he wants to be his friend, and see Koyuki again
- all the lower moons (not the demons, the lower moons slayer version) died thinking that the others survived (except for Rui)
- in the fight against upper 1, Nakime died thinking that Kyogai died, Kyogai almost died but he thought that Nakime was still alive
- Dōma felt like a terrible person, because everyone trusted him but he was hiding a basically suicidal plan from them, he told them to take care of their health while he was seriously affecting his, he listened to all their problems and emotions and helped them deal with them while deep down he wanted someone to explain him how to understand emotions
- the thought of Kotoha hating him for leaving Inosuke all by himself always haunted Dōma, it scared him, he didn't want his first best friend ever to hate him but he still wanted to avenge her, but Kotoha welcome him with open arms in the other side "I wanted you to take care of him, to make sure he was alright and you did until the very end, not only that, you gave him a world of peace and calm, thanks to you he now lives in a beautiful world without demons"
- on Kotoha and Dōma's birthday, Inosuke brings 2 plates with their favorite foods to their graves and eats with them. He hates wasting food and yet he never stopped this tradition
- Nezuko always wonders who the Hashiras are actually doing, because in their letters they always respond with such kindness and sweetness but she doesn't think they're really okay, after all that kindness comes from all the suffering and the pain of losing so many loved ones at once
- after learning about Dōma's backstory, Kaigaku couldn't help but wonder if he got sexually assaulted, but he refused to ask him about it since he consider it very touchy and private, even after his death he doesn't regret never asking, he prefers to forever live with the doubt than asking something that might have trigger him and remained him a traumatic experience
- when Kaigaku turned 24, Zenitsu started crying way too hard because now he only had one year left and he was done with loosing people who meant so much for him "Is no fair! No fair! No fair! No fair! I don't want to lose anyone else I'm tired of losing people over and over again" seeing that broke Kaigaku's heart, he wanted to stop time but instead he promised him that they'll be brother everytime they're reborn
- Inosuke to Hakuji when he died at 25 "I knew it was a bad idea to get attached to someone again, we didn't have enough time, I lost someone again, I knew you were going to die once you turn 25 and yet I let myself get attached to you and for a moment forgot about that, but honestly I don't regret it, you remained me that loving is beautiful and that I shouldn't feel bad because I keep losing them, because as long as we're alive good-byes are inevitable, thank you for that, I hope we can become friends again if we met again in another life"
- Ume gave Yuichiro the poison that Dōma created based on Shiane's techniques so that he would not suffer while he died (Yuichiro and Amane are swapped with Tamayo and Yushiro)
- Rui sometimes does Enmu's trainings because it helps him remember all their memories together
- Rui and Enmu sent each other letters constantly, when Enmu died Rui would unconsciously keep writing letters to him but then he cried on them because he remembered that he had no one to send them to
- before the news that Enmu died Rui wrote him a letter, when his crow told him he hugged the letter very tightly that he crumpled it and rewrote it to leave a well-made letter on his grave
- when Muzan's daughter and Rui became friends, she read all the letter he writted for Enmu and got a bit sad that such nice letters that would have surely made him happy were never read by him and will never be responded
- Muzan's daughter eventually took Enmu's place in Rui's life, they refer to each other as siblings and send each other letters all the time, the same with the Shabana's they took Douma's place in the lives of all the ice mansion's kids and vice versa
Guys, Can you help me give Muzan's daughter a name? Cause I have no idea if she has a canon name or if she's a nameless character
