Muichiro Tokito/Relationships

Tanjiro Kamado
During their first few encounters, Tanjiro and Muichiro held a strained relationship. Muichiro reprimanded Tanjiro by flicking a stone at his head after the latter interrupted Kagaya Ubuyashiki's speech, and Tanjiro was bewildered by Muichiro's rude treatment towards Kotetsu at the Swordsmith Village. However, after hearing Tanjiro's advice about helping others, Muichiro was influenced enough to alter his mindset, saving Kotetsu and Kozo Kanamori during Gyokko's attack on the village. After subsequently regaining his memories, Muichiro and Tanjiro became good friends, with Muichiro showing heavy bias towards Tanjiro when they trained together during the Hashira training session.

After hearing about Muichiro's death at the hands of Kokushibo, Tanjiro shed tears over the loss of his friend and vowed to himself he would continue fighting hard.

Yuichiro Tokito
Yuichiro was Muichiro's elder twin brother, who lived alone with him after their parents' deaths up until his own demise. Yuichiro was cynical about their passing and stated that Muichiro's kindness and self-sacrifice reminded him too much of their father. When Muichiro was considering joining the Demon Slayer Corp., Yuichiro demanded that Muichiro never spoke of it again. After Muichiro's own death, he meets Yuichiro again, who angrily states that that he died too young, breaking down in front of his younger twin brother and showing that he had always cared for his brother and was sad of his passing.

Kokushibo
Muichiro is the descendant of Kokushibo, a former Demon Slayer during the Sengoku era, who later became Upper Rank One.

When he first meets his ancestor in the Infinity Castle, Muichiro is shrouded by an intense fear completely new to him from the Demon's overwhelming presence. Kokushibo feels a sense of familiarity from Muichiro, later confirming that he is his descendant by blood. When he tells Muichiro of their relation, the Mist Hashira is shocked and refuses to believe him, instead managing to immediately calm himself which impresses the Demon. Muichiro's abilities at his young age continue to surpass Kokushibo's expectations to the point where he proposes to have Muzan Kibutsuji turn him into a Demon.