Try the Demon Slayer Name Generator

Start with the family name, because in Demon Slayer the family name does the talking. Kamado means stove. Rengoku means purgatory, a place of fire. Kocho means butterfly. Each one hints at what the person can do. So pick your breathing style first, find a Japanese word that fits it, and make that the family name. Then add a short first name with two or three sounds, like Tanjiro, Zenitsu, or Inosuke. Family name first in Japanese, first name first in English.

Four steps. One, tap the button and pick a breathing style: water, flame, wind, stone, thunder, or one you made up. Two, the generator gives you a family name that hints at that style, plus a first name. Do not like it? Tap again. Three, it draws your slayer in a black uniform with a patterned haori and a katana, with the breathing effect around them. Four, save the picture or make another. It takes about 30 seconds.

The show hides clues in the names. Kamado means stove, and the Kamado family sold charcoal and danced with fire. Rengoku means purgatory, and Rengoku is the flame user. Kocho means butterfly, and she uses insect breathing. Kanroji means sweet dew, and she uses love breathing. Tokito means time, and he uses mist breathing. The name is a small riddle. When fans hear it, they guess the element before the sword is drawn. Your OC can do the same.