The villains in the fanfic can also be quite memorable. If the writer creates a really menacing and complex villain, they can steal the show. For example, a villain who has a personal vendetta against McClane and uses his intelligence to try and outwit him at every turn.
John McClane is surely one of the most memorable. He's the tough - as - nails hero we know from the Die Hard movies. His quick thinking and ability to handle dangerous situations are what make him stand out. In the fanfic, he might have some new character traits or face different types of challenges that make him even more interesting.