Crux is the name of quite a few bands:
1) a British Oi! band from the early 80's
2) a Melodic/Post hardcore band based in Slough, UK
3) a Black/Thrash Metal band from the Czech Rep. (1990-1993) (go to the Crux (CZ))
4) a hardcore/punk band from Portland, OR (1993-1998).
5) a Sydney, Australia-based noise-pop band (mid-90s).
6) a metal band from Werne, Germany.
7) a Polish Avant-Garde alternative band (current)
8) a Christian band from Estonia.