It depends on many things. Very young children should probably not play it. Is it Warhammer Online or not? If it is online there are many adult players that may say things not appropriate for children. If it is offline play it yourself to judge the level of violence.
While Warhammer is rated T for teen (13+) the ultimate decision is made by parents, weather they want their kids to play the game or not. This game is very old and in meets older standards which were more strict than they are now.
