Well, 'naruto is a hollow fanfiction' might be a really unique take on the Naruto universe. If we consider 'hollow' in a more general sense, like an empty or void - like state, it could be a story that explores Naruto in a state of emotional or spiritual hollowness. Maybe he has lost his purpose or something has made him feel empty inside, and the fanfiction delves into that aspect of his character in a new and creative way.
Since 'hollow' can refer to a concept in certain fictional universes like the Hollows in Bleach, it's possible that in this fanfiction Naruto is given characteristics or put in a situation related to that. For example, he could be transformed into a Hollow - like being, or he might have to fight against Hollow - like enemies. It could also be a more metaphorical use of the term, where Naruto's world or his relationships are made 'hollow' in some way, and the story unfolds around that central idea.
Chapter 228, "Younger Brother is the Number One Hater?!", is the clearest early answer because it turns Mr's situation into a concrete plot event. The chapter gives readers a real answer by opening on Huo Ziyang had not stepped out of the house for a whole week.
Chapter 341, "Whose Child Is Jiang Cheng Really?", is the clearest early answer because it turns Whose Child Is's situation into a concrete plot event. Early on, Wei Dong glanced at his wife who had followed closely behind and....
Chapter 395, "She's Not Trying to Use Under-the-Table Tactics, Is She?", is the clearest early answer because it turns Director Shao's situation into a concrete plot event. Early on, He had thought that Jiang Li wanted the lead role to control the....
Chapter 318, "I Shouldn't Have Given Birth to You in the First Place!", is the clearest early answer because it turns Ruofang's situation into a concrete plot event. It opens with Jiang Cheng glanced at the pink and white building from the bus.
Chapter 497, "Carefully Raised a White-eyed Wolf", is the clearest early answer because it turns Ren Yue's situation into a concrete plot event.
Chapter 290, "The Jiang Family is to be Destroyed", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event.
Chapter 227, "There's Something Wrong with This Stepmother", is the clearest early answer because it turns Something Wrong's situation into a concrete plot event. The chapter turns that into something concrete by moving from Your Four Pillars of Destiny is very strong, with wealth, authority,...
Chapter 228, "Younger Brother is the Number One Hater?!", is the clearest early answer because it turns Yellow River's situation into a concrete plot event.
Chapter 389, "Slaughter Pig Platter", is the clearest early answer because it turns Xu Huiqiu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Jiang Li gave Xu Huiqiu a meaningful look and finally voiced the...
Chapter 556, "Five-Year College Entrance Exam, Three-Year Simulation", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event. A useful checkpoint is the way the scene starts with After finally settling down, it wasn't long before Jiang Yan started...