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 and after they're parents died they were all by themselves. Yuichiro was cynical about his parent's deaths and stated that Muichiro reminded him of they're father. After Muichiro dies he meets Yuichiro again stating that that he died too young and that the 'Mu' in Muichiro is the 'in' in Infinity showing that he all ways cared for his brother and was sad of his passing.

Kokushibo
Muichiro is the descendant of Kokushibo, a 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.