Tanjiro's ancestor was a good friend of Yoriichi and arguably was one of his only true friends. Therefore Yoriichi gave the earrings as a gift, and since then they have been passed down the generations until they reached Tanjiro.
After his mother Akeno gave him his signature Hanafuda earrings, Yoriichi realized he received them because his family had considered him deaf.
So the only reason Muzan is afraid of Tanjiro is because of the Hanafuda earrings he possesses, which acted as a reminder of his downfall. nxt. Hanafuda Earrings are a symbol of Sun Breathing users, traditionally passed down from generation to generation as a family heirloom.
In the series Demon Slayer, the earrings are an heirloom passed on from Tanjiro's father and are a symbol of Sun Breathing Style fighters. This is one of the early signs that Tanjiro comes from this legacy and is important for his character journey.
Despite not being a key character in Demon Slayer, Tanjuro had an important part in Tanjiro's life. Tanjuro was proven to be a remarkably powerful person, despite not being a demon slayer and having a sad sickness that renders his body terribly feeble.
Yoriichi had lost his wife and unborn child to demons, and he had a fateful encounter with Muzan Kibutsuji, the Progenitor of Demons. Yoriichi defeated Muzan in an instant, but he had a question for him before eliminating him, which allowed Muzan to escape.
The warrior Muzan feared was a swordsman named Yoriichi Tsugikuni. Yoriichi was the only slayer before Tanjiro who came close to killing Muzan, and the flashback of their fight occurred in Chapter 187.
Gyomei Himejima, the Stone Hashira, is the strongest Hashira in the Demon Slayer corps in terms of strength and swordsmanship. He is the only person who uses spiked flails and an axe instead of standard swords to kill demons. Such a weapon takes immense precision and soundness to use without inflicting personal damage.
Tanjiro certainly did a lot of good with his Water Breathing techniques, but his ability to use Sun Breathing both gives him an edge in battle and allows him to stand out among the incredibly powerful Hashira he fights alongside.
Tanjiro is a prime example as he only became a Demon Slayer and got his black Nichirin after a demon Human Slayer-ed most of his family.
Since he didn't know anything about the Blue Spider Lily medicine, he needed others to find the plant for him by happenstance. This is the general reason why Muzan turned Nezuko into a demon. More specifically though, was the fact that Nezuko was of Kamado blood.
Akaza was also one of Muzan's favorite demons out of all his subordinates. The reason behind this is Akaza's extreme loyalty to his master. The Upper Rank Three demon was always sent away on special missions, something the Upper Rank 1 and 2 were often denied of.
Moreover, while she was asleep, Urokodaki performed a unique hypnotism on Nezuko, making her believe that all humans are her family and she must not hurt them in any way. With her immense fondness for humanity, Nezuko broke out of Muzan's control, becoming free to do anything at her will.
Many Kimetsu no Yaiba fans deduce that Yoriichi is Tanjiro's father, but that isn't the case. However, Yoriichi is responsible for teaching Tanjiro's ancestors the Hinokami Kagura, which has been passed down for generations.
Demon Slayer's season 3's latest episode has left fans on edge with Tanjiro's discovery of Yoriichi Tsugikuni's Type Zero sword.
Despite looking very similar and having the same unique colored hair, Tanjiro is not related to Yoriichi through blood.
In the Demon Slayer Corps, the Hashira is a group of the strongest and most reputable swordsmen who have defeated members of the Twelve Kizuki. Yet, for some reason, Tanjiro Kamado, the series' protagonist, never becomes a Hashira.
1 Yoriichi Tsugikuni
Yoriichi was the very first user of the Breathing Styles and he came up with Sun Breathing, a powerful breathing form that is known to be the most effective against demons.
1. Gyomei Himejima – The Stone Hashira.
For those who have watched only the first season of the anime, they will be surprised to know that Muzan turns into a woman in the second season. He keeps transforming in order to hide his true identity, and he's even known to change into an 11-year-old child to hide from Demon slayers.
1 Muzan Regretted Killing His Doctor
He shows his most human side to fans, wherein he admits to regretting murdering his doctor. He comments that had he been patient, the doctor would have cured him, and he would never have turned into a demon.
The only reason why Muzan hates Doma is because of his insincerity and lack of emotions. This might sound odd, expecting emotions from a demon, but even a demon has to retain such tendencies to keep things in order.