Seeing the loss of human lives and the ceaseless destruction caused by the demon, Tanjiro's was overcome with rage, causing his eyes to start bleeding. He spoke to Daki about how demons trample over the lives of normal humans who, once dead, will never return.
Not one to back off from a fight nor is he one to overlook injustice; he has fought and slain several demons, but his battle with Daki pushed him over the edge, and with unbridled rage boiling within him, Tanjiro's eyes became bloody.
Daki quickly identified the memory as Muzan's, in which a man with the same auburn hair, Hanafuda Earrings and forehead scar as Tanjiro delivered an equally foreboding speech to him.
After Tanjiro got close to the Demon King, Muzan nonchalantly slashed out Tanjiro's eye, and later stated that his attacks were too fast for him to detect through smell.
Muzan refused to die and when he was finally about to breathe his last, he transferred all the blood to Tanjiro in the hope that he would become the successor and carry out his will.
Don't go! DON'T LEAVE ME HERE! Muzan speaks his final words as he loses control over Tanjiro.
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.
So, in conclusion, her coming from a Sun Breathing user's lineage and not relying on human substance are perhaps the reasons for her immunity. Hence, Muzan was searching for the Blue Spider Lilly, a flower that was a crucial ingredient in the medicine used by the doctor who saved his life.
Tanjiro's sun-breathing technique, Hinokami Kagura, allowed him to cut through Daki's obi sashes with ease. This created the opening he was looking for, allowing him to almost slash Daki's head off.
The two known demons who broke free of Muzan's curse are Tamayo and Nezuko. Tamayo was able to break free of the condemnation when Yoriichi fought Muzan, nearly killing him in the process. During this weakened state, Yoriichi let Tamayo go, free her from Muzan, and free her from the curse.
Though now he's on his way. Daki too has reached new heights of power. She absorbs the remains of the belt demon, her hair turns white and green, and she gets uh, more veiny. But she is shocked when Tanjiro's Sun Breathing not only cuts through her belts, but actually burns her.
Muzan himself never thought highly of Daki and didn't reciprocate her devotion whatsoever, only ever talking to her to sweetly manipulate her into defeating Demon Slayers on his behalf.
Tanjiro faced a swamp demon in the first season as a result of the missing teenage girls, the demon siblings, Daki and Gyutaro; Enmu, the sleep whisperer, and many others. Rui, a lower-ranking demon, is his most formidable foe.
Daki received a third eye that Gyutaro had implanted on her forehead. Her reflexes were quicker, her movements were sharper and her strength improved quite drastically. If we take a closer look, it was Gyutaro's left eye that was implanted on her forehead.
In episode 6 of Demon Slayer season 2, Nezuko entered a berserk state to protect her brother Tanjiro, causing her body to develop into that of an adult. She loses her gag, grows a single horn and gains vine-like patterns across her body.
The Samurai not only insulted Gyutaro in front of Daki but also made fun of his malnourished body and disease. As Daki was unable to tolerate the insult of her brother, she took off her Kanzashi and stabbed the left eye of the Samurai.
Nezuko Obliterated Daki with Blind Rage.
Nezuko is at least stronger than Daki, meaning that if Muzan could bring her back under his control, she would certainly qualify for the most prestigious title a demon can hold: a member of the Twelve Kizuki. Thanks to Nezuko's remarkable strength, she would have to be an Upper-Moon.
However, against all odds, Tanjiro along with the rest of his crew were able to defeat the Upper Moon 6. This was also the first time he activated his Demon Slayer Mark as well. Fans absolutely loved this fight in the Entertainment District arc.
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.
However, since the Blue Spider Lilly was found to only bloom during the day, that may explain why Muzan never found them after spending so long looking. As a demon, Muzan would obvioulsy not be able to go out and find them due to the devastating effects of sunlight on his body.
Secondly, Muzan would probably… eat Nezuko and Tanjiro in the hopes of obtaining their sun-resistance abilities, and also since he wouldn't be able to convince them to become demons to work under him. This would allow him to become the ultimate demon.
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.
Black is the most mysterious color of all the blades, and is held by the main character, Tanjiro. It is a rare blade and represents the sun; it also holds a theory that the demon slayers who own this sword are not to live a long life.
The black blade represents the Sun and is surrounded by prejudice and misconceptions, as historically every demon slayer who held it lived a short life. This could mean that Tanjirou is destined to break the pattern and set a new legend for black Nichirin blades in the Demon Slayer universe.