There are several uses of "as such." One is what Anna explained. In your sentence, I think "as such" means "as heroes." The "such" acts like a pronoun, so that you don't have to repeat the word "heroes." Another way of thinking about it: "as such" is short for "as being such a thing." Examples: "She is my boss, but I don't think of her as such" = "I don't think of her as my boss" = "I don't think of her as being such a thing."