Matador's opponent

TORO

This fierce animal is often associated with Spanish culture and might charge when provoked in an arena. Think of the bull in a traditional fight.

"Matador's opponent" refers to the bull in a bullfight, which is called a toro in Spanish. The clue plays on the traditional rivalry between the matador (the bullfighter) and the bull itself, a central element of Spanish bullfighting culture. Since crosswords often use foreign words for conciseness, toro fits as the straightforward answer.