Begin with a hook. Maybe start with Big Boss in a completely unexpected situation that is related to the crossover. For instance, if it's a crossover with a fantasy world, start with Big Boss waking up in a magical forest surrounded by strange creatures. This will immediately draw the reader in. Then, gradually introduce the rules and elements of the new world as Big Boss discovers them. As you write, keep in mind the motivations of Big Boss and how they might be affected by the new environment and characters he meets.
First, decide which two universes or characters you want to cross over. For the 'big boss crossover fanfic', you need to choose a world that would make an interesting contrast or combination with Big Boss's own world. Then, come up with a basic plot idea, like a common enemy or a shared goal.
You should also research both the Big Boss character and the elements of the other crossover part. If it's a crossover with a science - fiction series, learn about their technology, society, etc. This will help you write more believable interactions. For example, if it's a crossover with Star Trek, understand how the Federation operates. After that, create your main characters' voices. Big Boss has a very distinct personality, so make sure to keep that intact while also allowing for growth and change in the new situation. And start writing, don't worry too much about making it perfect at first.
Chapter 159, "Blood and Flesh Wall, The Leader Hasn't Broken Through Yet?", is the clearest early answer because it turns Xia Chuan's situation into a concrete plot event. The chapter gives readers a real answer by opening on The hundred-meter-thick wooden walls, arranged in a slanted cross... and ending on In an instant, a dozen Cold Beasts were floundering at the wooden....
Chapter 216, "Great Medicine, Going Out, Turmoil in Longyou (Part 2)", is the clearest early answer because the rescue effort creates visible on-page results. A useful checkpoint is the way the scene starts with Looking at the person directly across from the big pot, still talking... and follows through with Old Chen, long time no see..
Chapter 157, "The Disappearance of the Cold Beast, Breakthrough Tide", is the clearest early answer because Xia Chuan finally turns buildup into a real advancement. The chapter turns that into something concrete by moving from Within five hundred meters of the perimeter, all low-level Cold... to Not only unafraid, but there's also a kind of near-mad obsession..
Chapter 225, "Council at Long Mountain, Li Xuanling's Decisive Action (Part 2)", is the clearest early answer because it turns Li Xuanyan's situation into a concrete plot event. The setup is What Fourth Brother said makes sense, I agree too." In fact, in Li..., but the pressure keeps building through Then, hearing Li Xuanyan also falsely expressing agreement, he....
Chapter 174, "Integration, Manifestation of Yang, Conflict of the Director", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. The chapter gives readers a real answer by opening on Seeing that the two did not respond, Meng Ao directly changed the... and ending on But thinking about it carefully, these folks from Mirror Immortal,....
Chapter 244, "Besieged, Strength, and Rescue (Part 2)", is the clearest early answer because the buildup finally cashes out in a real clash. A useful checkpoint is the way the scene starts with Just like last time, this time he could only crash into five or six... and follows through with It wasn't just these two; everyone from Long Mountain, including....
Chapter 203, "Shock, Prisoner Rules, and What Constitutes Guilt?", is the clearest early answer because it turns Xiang Liang's situation into a concrete plot event. It opens with Four families, numbering five to six thousand people, gradually... and closes on how is this possible..." Recalling what his father just said, Xiang....
Chapter 167, "Seizing the Mirror, He Yuanhun's Confidence", is the clearest early answer because it turns Great Xia's situation into a concrete plot event. The chapter turns that into something concrete by moving from Xia Hong, thank you!" A gentle voice suddenly emerged from beneath... to If earlier Xia Hong had harbored any expectations that all this was.... What makes it stick is that the chapter closes with "Xia Hong, please allow me to explain.
Chapter 226, "Beehive Incident, Lin Ye Is Dead", is the clearest early answer because the violence around Channel becomes final instead of hypothetical. The chapter gives readers a real answer by opening on The Hive Station is underground, with a total of twenty-seven... and ending on The main area still has over six hundred Earth-digging Realm and more....
Chapter 228, "Justified Cause and the Infiltration's Story", is the clearest early answer because it turns Hou Ming's situation into a concrete plot event. The chapter turns that into something concrete by moving from Not only Hou Ming, Hou Bing, Hou Ying, and the severely injured Lin... to Great Xia and the Beehive have been good neighbors for a long time,....