Hatred of magic is the primary concept of Battleragers.
You can have various roles but they all should incorporate hunting mages. If you don't, then your role doesn't fit well the cabal (it can be a great role and you can go solo or join other cabals. Like a druid in outlanders who hunted mages).
Similarly, you can't create valid roles for other cabals if it violates their primary concepts.
Examples:
- a tribunal who let some criminals live (because they pay him or his mother is outlander)
- a fortress member who loves dark elves and thus don't hunt them
- an outlander who likes money and adamantatite armor (because it's shining and gives good damroll).
Those roles don't fit corresponding cabals. True, if you have dumb leaders/immortals you can get away with it as you can get away with anything else. But that doesn't make wrong things right.