I’ve been mulling this over for a while. I’m going with…Callisto! (Aside from her tentacle arms period.)
Badass eye-patched leader of an underground group of exceptionally outcast group of outcast mutants? Boom. Her full bio.
Although…Callisto did get her ass kicked by Storm. And Storm sported a killer mohawk back in the day AND lived on the streets for a while. Storm’s hardcore.