Board Thread:General Discussion/@comment-23.112.163.121-20171108072642/@comment-26397825-20171110230356

You can have multiple people with the same colour aura. Glynda and Blake have purple, Sun and Yang have yellow, Nora and Ren have pink, Qrow, Ruby and Pyrrha (and maybe even Raven) all have red aura. There’s only so many colours in the colour wheel and many more characters than that, so not everyone is going to have a unique colour.

A unique shade, however, might be possible.