Demon Slayer is more than just a "monster hunter" anime in the same vein as D.Gray-Man, InuYasha or Jujutsu Kaisen. It also humanizes the demons because they were once human, and this often reflects in how they think and behave as supernatural creatures of the night. A good example of this is the belt-slinging Daki, whose name carries serious meaning.
Daki assumed a human disguise while living in the Entertainment District, calling herself Warabihime, but she had another name as a human girl: Ume. All of these names carry serious meaning for the character, explaining her ever-changing nature from human to demon and wannabe princess. The kanji used to write these names makes it even clearer.
The Names Ume And Warabihime
All three of this character's names carry meaning, and sometimes, each name has more than one meaning depending on the context or who is speaking. The character was born with the name Ume, and it can be written with the Kanji for "plum." That sounds innocent enough, and the same is true of her nickname Ume, which might be read as "white plum" -- possibly a reference to her pale hair in her girlhood in the slums.
However, her human name Ume carried a darker double meaning, and her brother Gyutaro knew it. Ume and Gyutaro's mother died of syphilis, and Ume may have been named after it. Although named Baidoku, that illness's kanji can be read in other ways, and one of the kanji in Baidoku can be read as "Ume," hence the character's unflattering name and its association with poverty, illness and misery. Right away, it was clear that Ume/Daki had a life of hardship and woe, and she had nothing but her natural beauty and her protective brother to rely on. It's as though she were branded a failure from birth.
After becoming a demon at the hands of Muzan Kibutsuji, whom Ume adores, Ume began working as an oiran in the Entertainment District and went by many names, including Warabihime, to maintain her facade. This particular name also has meaning, with the character "warabi" referring to the bracken fern plant and "hime" being a word for princess.
Notably, bracken is a common plant eaten in Asia, including in Japan, but it might be linked to increased cancer rates and can cause health problems if not prepared correctly. This may allude to Warabihime appearing harmless but being unexpectedly dangerous on the inside, and she is deadly if people don't handle themselves correctly around her. And, of course, Warabihime fancies herself a lofty princess, a beautiful and perfect being who is desperate to distance herself from her difficult childhood. She is a demon now and identifies strongly with it. Her past life is dead and buried.
The Meaning Of The Name Daki
Most of all, this character is known by the name Daki, and that appears to be her demon name, as most other demons seem to know her by that name too. This name is made up of two kanji, the first of which can be read as "degenerate," "descent" or "lapse into," suggesting a person or thing that was once noble or lofty but became corrupted, dark and twisted at some point.
Sure enough, Daki descended from innocent humanity into a depraved, bloodthirsty demon, and even if Daki thinks that's an upgrade, it's actually a fall from grace. No human has become a better being by mutating into a demon so far in Demon Slayer, and whatever Daki herself may think of it, her transformation from human to demon twisted her into something monstrous, low and vulgar.
The second kanji in Daki's name can be read as "princess," the same as the "hime" character in Warabihime. This means that the character views herself as a wannabe princess, whether she's dressed up as a high-ranking oiran or operating as a demon, and she thinks highly of herself in either mode. Whether she's the queen of the Entertainment District or shedding blood as a demon, Daki is certain that she has become royalty among the peasantry that is humanity. But as Tanjiro and Tengen Uzui proved, she is anything but a princess. She is a vulgar monster with delusions of grandeur, and her life ended with the Entertainment District itself. Her hubris will never save her from a Nichrin blade.
