Uhh demon slayer spoiler, The character Shinobu Kocho gets attacked by Douma upper moon six and his attacks slash through her, making her lungs collapse and finally he absorbs her into his body
Actually I think it's better to color with solid colors and for shading you should use a colder variant of the color , for example if the hair is blue you would shade with a less saturated (and darker)purple (it depends on how saturated you want it though) and always remember how colors combine, like blue goes along with orange