Sanemi Shinazugawa/Relationships

Genya Shinazugawa
Genya is Sanemi's younger brother and only living sibling. After a Demon attack befell their family, Sanemi and Genya were the only ones who survived the incident. However, after being branded a "murderer" by Genya, their relationship began to worsen and decline until the two split and went their own ways. It is revealed during the battle with Kokushibo that despite the whole incident, Sanemi still heavily cared for his younger brother and actually wanted him to live a normal life without the threat of demons. Genya is moved to tears and apologized after hearing Sanemi's reasoning behind his rudeness. After their battle with Kokushibou, Genya apologized again for blaming Sanemi and thanked his brother for protecting him before succumbing to his wounds and crumbling into dust, leaving Sanemi stricken with grief.

Kagaya Ubuyashiki
Sanemi shows deep respect towards Kagaya, believing that he is the most important person in the Demon Slayer Corps who should always be first priority. During Tanjiro's first meeting, after angrily threatening to kill him for head-butting him to the ground, Kagaya arrived at that moment and Sanemi immediately switched his demeanour.

When he first met Kagaya, Sanemi seethed with anger at how he could smile as the leader responsible for numerous deaths and had assumed that he was just letting Demon Slayers die while he was sitting in the safety of the Hashira to protect, saying that his life wasn't the top priority. After insulting him in front of the other Hashira, Kagaya gently apologizes, surprising Sanemi, and told him his body cannot handle the physicality of combat. Kagaya tells him he can treat him in any way he wants, he is only respected because the others do so out of good intentions, and reminds him to focus on his duty as a Hashira as his only wish. Sanemi gained more respect for him when he learned that he memorized all the names of the fallen demon slayers, including his friend who had died.

Sanemi was heavily angered when Kagaya had died in the explosion in order to slow down Muzan Kibutsuji and lamented his inability to save him on more than one occasion.

Nezuko Kamado
When they first met, Sanemi had a deep hatred for demons. He taunted Tanjiro by stabbing Nezuko multiple times from within the box with his nichirin blade and tried to prove Kagaya Ubuyashiki that all demons eat humans by trying to force Nezuko to devour him by wounding his arm since he possesses the rich marechi type blood that is highly nutritious to demons being equivilant to eating a hundred humans. After the battle with Muzan Kibutsuji, Sanemi seems to have cooled down after awakening from his long rest. He somehow runs into Nezuko again and meets her for the first time as a human. Asking if his wounds were ok, he bluntly replies that his wounds are fine. He then apologizes to Nezuko about everything he had done to her in the past. He told Nezuko that he was asleep during the battle that happened after they killed Muzan. Nezuko tells Sanemi that she was asleep for two whole years and that she loves to sleep which caused Sanemi to see Genya in Nezuko's expression. He gives her a headpat and smiles at her before parting ways.

Tanjiro Kamado
Sanemi and Tanjiro did not get along well when they first met at the Hashira's trial. At this trial, Sanemi believed Tanjiro to be a “moron” for not only travelling with a demon, but also for believing said demon would “fight to protect humans”. Tanjiro quickly stepped in to attack Sanemi after he stabbed Nezuko, successfully landing a headbutt on him (albeit, Sanemi was distracted by Giyu’s outburst).

Even after the leader of the Demon Slayer Corps himself, Kagaya, requested the Hashira to accept Nezuko, Sanemi stubbornly persisted otherwise. He was even willing to act upon his beliefs when being informed that Tanjiro, Urokodaki, and Tomioka would all commit seppuku.

Once Nezuko had passed the trial and refused to attack Sanemi, Tanjiro asked the Master to headbutt Sanemi for each time he stabbed Nezuko. Tanjiro likely would've done so if Muchiro and the Kakushi had not intervened.

Giyu Tomioka
Sanemi and Giyu seem to not have a very good relationship as their personalities are quite different. Sanemi with his usually loud and abrasive speech while Giyu is kept calm and quiet. The only time there is respect shown is when Kagaya is in the room.

It is shown that Giyu attempts to have a friendly gesture towards Sanemi when Tanjiro offers to eat ohagi together. After the Demon Slayer Corps is disbanded, the two Hashira look to each other and smile, since their long journey finally ended. They even eat together at one point, mending their relationship.

Masachika Kumeno
Masachika was Sanemi's close friend and colleagues in the Demon Slayer Corps. He saved Sanemi from a demon attack and healed his wounds. They soon found a brother like friendship within one another. Unfortunately, Kumeno would end up killed in a battle against Lower Rank One, Ubume. Sanemi, still grieving his death, even lashed out at Kagaya for thinking he would send Demon Slayers to their deaths haplessly.

Masachika's will was given to Sanemi by Kagaya Ubaushiki, which drew Sanemi to tears.

Kanae Kocho
Not much is currently known about Kanae and Sanemi's relationship. Gyomei Himejima claims that Sanemi had a crush on Kanae, though we do not have confirmation from Sanemi. We also do not know if these feelings were reciprocated.

In Kimetsu Academy, Sanemi is claimed to enjoy talking to Kanae in his free time.