Tanjiro visits Asakusa in Tokyo after reports of Demons in the city.
Tropes associated with Asakusa Arc:
- Alas, Poor Villain: Tanjiro and Tamayo express sympathy for Susamaru despite her attempting to kill them because she was truly loyal to Muzan and he repaid her by destroying her body and leaving her to die.
- Arc Villain: Yahaba and Susamaru are the main enemies that Tanjiro, Nezuko, Tamayo, and Yushiro encounters, as Muzan sent them to kill Tanjiro, mainly because of seeing the hanafuda earrings that reminded him of someone.
- Badass in a Nice Suit: Say what you might about Muzan, but his dressing style is impeccable.
- Bad Boss: Muzan, to the T. He places a curse on the demons he creates that will destroy their bodies and leave them unable to regenerate if they so much as say his name, leaving them to suffer as a pile of blood and organs until the sun destroys what's left. Muzan is so paranoid about his enemies finding out any information about him that he would rather let his minions die in agony than risk them revealing any more information, no matter how small it is.
- Bait the Dog: Muzan seemed to be a well-adjusted young man, but he turns a man into a Demon just to take down Tanjiro on the off-chance.
- Berserk Button: Muzan after seeing Tanjiro's earrings.
- Yahaba hates touching dirt.
- Big Bad: Muzan Kibutsuji establishes himself as this to the series.
- Chekhov's Gun: Tanjiro's earrings.
- Combination Attack: Yahaba uses his Vectors to manipulate Susamaru's temaris, allowing them to move like living creatures, avoiding attacks and striking enemies from odd angles. Their excellent coordination is particularly impressive when you take into account the fact that they have only been together for one day and that demons only rarely work together.
- Cruel and Unusual Death: After Susamaru accidentally revealed Muzan's name to Tamayo and Yushiro, Muzan's curse takes hold of her and three large arms came out from her mouth, chest, and stomach which then rip her to shreds, leaving her as nothing but an arm, an eye, and a pool of blood, with her getting finished off by being burned away in sunlight.
- Establishing Character Moment: A very efficient one for the Big Bad of the manga. Muzan seems to be a kind man with his family, but the moment he spots Tanjiro, he turns a man into a Demon and tries to get him kill several humans as a distraction. He also later kills a group of people for petty reasons, and one for simply being there, showing him to be a vile, extremely petty and callous Demon.
- Everyone Has Standards: Tamayo is horrified when Yushiro plans to leave Tanjiro and Nezuko as decoys and run away. Yushiro backpedals immediately and says he was just joking.
- Find the Cure!: Tamayo tasks Tanjiro into collecting the blood samples of the Twelve Demon Moons to counteract Muzan's cells within Nezuko and other Demons, if possible.
- Foreshadowing: Tamayo surely has a lot of information about Muzan and his Twelve Demon Moons despite being one of the peaceful Demons.
- Genre Savvy: Muzan is smart enough to not let the Demons band together in order to avenge their transformations and the rise of their Horror Hunger.
- Hair-Trigger Temper: Muzan is shown to have a truly vicious one. Part of his Establishing Character Moment has him kill a pair of drunkards for insulting his appearance, and he inflicts a Cruel and Unusual Death on the woman accompanying them even though she didn't say or do anything to offend him.
- Horrible Judge of Character: Susamaru misjudged Muzan as she thought he's a reasonable man.
- Misanthrope Supreme: Muzan may have a family, but it's clear he hates mingling or having to do anything with humans other than eating them or converting them into Demons.
- Monster Progenitor: Muzan is the progenitor of the entire Demon race, excluding Yushiro, whom Tamayo converted using Muzan's cells as an emergency.
- Rain of Arrows: Yahaba's Blood Demon art.
- Saying Too Much: How Tamayo essentially makes Susamaru commit suicide-by-Muzan's cells. She made her blurt out Muzan's name and trigger his curse, leading Muzan's cells to destroy her body and leave her unable to regenerate.
- Serious Business: The udon salesman is less interested in the fact that Tanjiro left without paying than the fact that in his rush to follow Muzan Tanjiro didn't finish his meal.
- Speaking Up for Another: Played for Laughs. When Yushiro proceeds to insult Nezuko's beauty, Tanjiro proceeds to rant in his sister's defense after taking a moment to process that yes, Yushiro was talking about Nezuko.
- Taking You with Me: Yahaba tries to kill Tanjiro after being decapitated. Tanjiro only survives by various Water Breathing moves in quick succession.
- Token Heroic Orc: Tamayo and Yushiro. Tamayo has stopped eating humans for a really long time, and Yushiro, like Nezuko, hasn't eaten a single human.
- This Is Unforgivable!: "Muzan, you shouldn't be allowed to exist."
- Undying Loyalty: Yahaba and Susamaru, but more the latter, are truly devoted to Muzan. Too bad he doesn't return the sentiment.
