From the beginning of the series, Kibutsuji Muzan was established as the most fearsome demon in existence. He is responsible for the creation of all other demons in the series, of which most are still extremely fearful of him, as he has been shown to slaughter subordinates that displease him.
8 Kokushibo. He might be the Upper Rank One Demon and the strongest member of the Twelve Kizuki, but Kokushibo is actually one of the more reserved demons on this list. ...
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.
Shinobu Kocho's tragic backstory is one of the most heart-wrenching in Demon Slayer. She and her sister, Kanae, were orphaned at a young age after their parents were killed by a demon.
The Wind Hashira has one of the saddest backstories in Demon Slayer. His mother had turned into a demon and had killed five of his siblings. He was forced to kill his own mother in an attempt to save his only remaining brother, Genya.
And finally, let's get to the number one saddest death in the franchise, and of course, that's the death of the brightly burning Flame-Breathing user that is Kyojuro Rengoku.
She felt that only a man stronger than her could love her, so she worked hard to become a Hashira and meet the other Hashira, hoping her partner might be among them. Unfortunately, Mitsuri never got her wish. While battling with Muzan, she attacked viciously, losing both her arms in the process.
Neon Genesis Evangelion's Shinji is one of the most notable crybabies across anime. He gets overwhelmed often and has a lot of issues coping with social situations. Of course, Shinji has many reasons for expressing his melancholy so frequently.
Sanemi's blood is known to be enticing yet intoxicating to Demons, which he used to bait and stab Nezuko. Sanemi is clearly the least popular Hashira among Demon Slayer fans.
The only Demon he despises the most is the Upper Rank Two: Doma. It is quite a shocker that the second most potent Demon in the Demon Slayer is not Muzan's favorite.
