akane: aka, red, is part of it so its pretty obvious. though when i typed it, auto-suggestion gave me 茜. its the japanese name for rubia cordifolia, which is used to make a traditional shade of red dye of the same name. search up 茜染め (akane dyed) and you'll see some examples. i kinda liked researching the background behind this.
anyways akane the aka oni sounds nice. her having a color themed name fits in with the rest of the named supernatural characters, who ive seen when searching black channel up.