So this is going to be for the most part Izuku's relationship with each Hashira prior and current.

As the person who took care of him after the incident, Kanae acts like an older sister or motherly figure to Izuku. She feels sympathy for him and only wants Izuku to live a life of peace to feel a little shame knowing he chose to walk the path of the Demon Slayer in more ways than one. Though she has to dislike Muzan Kibutsushi, she doesn't like the possibility of Izuku having to fight his own father.

First learning of Izuku's lineage, Shinobu was uneasy with Izuku for obvious reasons. But after learning he wasn't dangerous, the Insect Breathing Demon Slayer accepted him and occasionally helped Izuku with making his own Breathing Style that fit him. Upon returning from Final Selection, she's also the one that tells Izuku of Kanae's passing for her to realize how hard this hit Izuku of all people. She hates the fact Izuku has to fight demons in the Corps, but knows there's no stopping him to only help where she can.

Izuku met Shinjuro when he was still a Hashira to notice the spirit of his late wife watching over him to know he's hurting a lot. One day in a drunken fit, Shinjuro attacked Izuku claiming him to be a demon for him to give a nasty gash over his torso. Knowing it would be bad for everyone if it's shown why Shinjuro did it or even the fact a member of the Demon Slayer Corps attacked another member, Izuku lied and said it was training that got out of hand. Shinjuro silently hates Izuku for doing this and thinks he's looking down on him due to his inferiority complex.

Knowing of what really happened between Izuku and his father, Kyojuro feels a great deal of respect for Izuku outside of the fact he's a demon fighting for humans. Seeing the skill and ironclad resolve Izuku has, Kyojuro feels happy having someone like Izuku in the Corps. The same could also be said about Kyojuro to Izuku. He sees the flame Hashira as a burning passion that isn't able to dissolve for both to train to better themselves to inspire the other.

For the most part, Tomioka doesn't care for Izuku thinking he would be better off keeping his distance. Seeing a weight on Tomioka, Izuku regularly gives him space and doesn't push into his personal life as he notices Tomioka's older sister's spirit around him trying to comfort him.

Meeting Izuku during an incident on a mountain, her and Iguro noticed Izuku fight and defeat dozens of demons as well as a current holder of Lower Five(not Rui). She was amazed with his power and offered to teach Izuku how to be at the level of a Hashira with Iguro. She began developing feelings for him and after beating her in a sparing match and seeing him accept her true self, she said that she'd marry Izuku.

Understanding the cursed blood lineage that Izuku has, Iguro somewhat relates to him with his snake Kaburamaru liking Izuku and resting in his hair to sunbathe. Due to his attraction to Mitsuri, Iguro hates Izuku greatly when the Love Hashira shows a bit of romantic interest towards him. He normally chases Izuku around whenever this happens as a form of his jealousy. Though he doesn't like how close Izuku is to Mitsuri, Iguro genuinely likes Izuku more than most.

Like all Hashira that met Izuku, he wasn't so certain of having a Demon in the Corps. However, Izuku proved himself in his missions and training for Tengen to see him as a 'dark flashy guy'. Izuku also had learned of his siblings and upbringing by his Blood Demon Art to avoid saying anything that may upset the upbeat Sound Hashira.

Gyomei had little trust for Izuku right off the bat and needed him to prove himself with undeniable proof. Knowing he's blind and someone who obtained the rank of Hashira in two months, Izuku has a lot of respect for him especially knowing he used to be part of a Buddhist temple to understand his distrust. Though he's not trusted by Gyomei, Izuku still sees the man as a respective father figure due to his gentle nature.

To make things simple, Muichiro scares Izuku. He met Muichiro later than everyone, but he mastered taking the rank of Hashira in two months as opposed to Izuku's two years. But what scares him more is a hint of cold blooded brutality that is etched inside his soul. A large amount of his brutality also confuses Izuku since his soul seemed more kind hearted than the brazen tongue. Since it gives him a headache to try and wrap his mind around, Izuku mostly tries to avoid talking to him, but doesn't dislike him.

Izuku doesn't know much about Sanemi since he seems to despise Izuku. In a single moment alone, Izuku tried to find out about him for Sanemi to tell Izuku that no matter how hard he tries, he's a demon and nothing will change that. This hurt Izuku a lot by what he wanted to prove, but tries to see his soul in order to find out why Sanemi holds so much anger to see his younger siblings and mother trying to tell him it's not his fault as well as the fact he's actually the type of person that holds the weight of the world on his shoulders and takes it no matter the cost. Though the chances in Izuku's mind is that they will never see eye to eye, he understands that the only way someone like Sanemi can find peace in this life is to have all the demons in the world meet their end.

Alright, that's everyone that's of importance. Hope you all enjoyed and this story will start in January. Hope you all enjoyed and thanks for reading.