He damaged the CAT with the sword, dividing it in two.
|( を ) わ＊る||
I divide it- also can mean 'smash a brittle object to pieces' like if you drop a mirror.
|( が ) わ＊れる||
it divides / it gets divided
role, but more general and figurative than just 役（やく）。 Gay dudes who are top or bottom - that's 役割。 If your role is 'the black sheep of the family," that's 役割。 The guy in the boy-band who is "the edgy one." The person on the reality -tv show who is "the crazy one."
The verb is 果たす（はたす）, as in XXX の役割を果たす（ to play the role of XXX)