Different clans have taken different roles when upholding the Masquerade. Like reconnaissance, stompin', leadership, magical stuff, etc. Some clans need each other, even if they don't like it. There's a sort of guild rivalry between them, but common threaths are quite common, resulting in lots of alliances. Of course; Jyhad is everywhere; so no one trust anyone. Unless blood bonded, that is.
Out-of-character knowledge +1