Tanjiro Is Everyone's Big Brother
There's a reason why people who watch/read Kimetsu No Yaiba fall in love with Tanjiro Kamado. Sure, on the surface, he's a pretty cliche action-anime protagonist. But, the more time we spend with him, the more his subtlety begins to shine. Tanjiro is the ultimate people pleaser, he wants everyone around him to feel happy, safe, and sound. It's why he's constantly in a state of "Caring Big Brother" that Inosuke so vehemently despises. The most extreme examples are when he buys ramen and baskets from villagers and insists on paying, when he looks after the kids in Kyogai's house, and when he mourns for the demons as they turn to ash. Just such a pure boy.
Feel, Hear, And Smell No Evil?
Now, this is a bit subjective, but it seems like some people have been overlooking it. Inosuke has an incredibly sensitive sense of touch, Zentisu can hear even the emotions of people next to him, and Tanjiro can smell so well he knows the best course of action to take.
These three all have their own gimmick. They're also most likely a reference to the old proverb "Hear no evil, speak no evil, see no evil". Obviously not in the senses themselves, but rather with one of their six senses helping them detect evil, which in this case are the demons.
Nezuko Is Actually Super Buff
Nezuko doesn't eat people; Tanjiro won't let her. He doesn't want her to become fully demon, and she obviously doesn't want to hurt anyone. So, in order to compensate for the lack of "nutrients," Nezuko is constantly sleeping. This also causes her to regenerate much slower than a normal demon.
But, oddly enough, Nezuko is incredibly strong still. Like, much stronger than the average demon. She wins in most contests of strength despite not having a strong build physically. This may be her own special brand of demon blood art, or it may be something deeper that we're just not aware of yet.
Muzan Has A Past With Tanjiro's Earrings
The main reason that Tanjiro and his sister had to fight a Termari throwing demon was that Muzan, the first of the demons, recognized his earrings. Tanjiro's "hanafune" earrings seemed to remind Muzan of someone who had almost killed him in the past. In the anime, Muzan has a very brief flashback and sends his goons after Tanjiro and crew, but many people might've missed just how similar this shadowy figure looks to Tanjiro. We won't spoil anything that pops up further in the story, but let's just say that this sort of foreshadowing is common in Shonen anime such as Naruto.
Muzan's Blood Is An Alternative Steroid
Throughout the anime so far, Demon's have stated multiple times that the more humans they consume, the stronger they become. But, what about Muzan's blood? It's the catalyst for turning humans into demons, and we've seen what too much of it will do to someone. So, what if an already strong demon is given more of his blood to drink?
Will they be able to consume more? This is another method of strengthening demons that has only been alluded to in the show. Our theory is that it works as both a way to grow and to increase the cap for how many humans a demon can ingest.
Zenitsu Ironically Can't Hear His Own Bird
