First, think about the character of the phantom brother. Decide on his appearance, like is he a pale, shadowy figure or does he look more normal but with a slightly translucent quality? Then, consider his backstory. Was he a victim of some sort of tragedy? This will help you build the foundation for your story.
You could start with a scene that introduces the main character's encounter with the phantom brother. For example, the main character could be in an old, abandoned house and suddenly feel a strange presence. This will immediately draw the reader in. After that, start to gradually reveal bits of the phantom brother's story through their interactions. Also, think about the setting. Is it a modern city or a spooky small town? This can add a lot to the atmosphere of your fanfiction.
Chapter 519, "I'm Here to Participate in the Program", is the clearest early answer because it turns Younger President Jin's situation into a concrete plot event.
Chapter 287, "Saved", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. It opens with For five consecutive days, the search and rescue team had not... and closes on Failing to obtain any news after numerous attempts, Lu Xingchao had....
Chapter 408, "You Can't Be on the Same Team!", is the clearest early answer because it turns Flash Change's situation into a concrete plot event. The chapter gives readers a real answer by opening on Zheng Xun fell silent after he understood the situation.
Chapter 581, "Where is everyone? Where have they all gone?!", is the clearest early answer because it turns Are's situation into a concrete plot event.
Chapter 376, "I'm Just Afraid You Don't Need Me Anymore", is the clearest early answer because it turns Crown Prince Jin's situation into a concrete plot event. The chapter gives readers a real answer by opening on The phone call fell into a long silence.
Chapter 300, "You're retaking the college entrance exam?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with I dropped out." Jiang Li said calmly.
Chapter 513, "A Public Stage", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Everyone was sharing their experiences in a few words, the banter...
Chapter 786, "Working at Chen'an?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. It opens with When Jiang Li left Taiqi's office building, it was already getting... and closes on She recognized that this must be the streamer Xiao Xue..
Chapter 761, "Can You Take Us In?", is the clearest early answer because it turns Aunt Feng's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Lili, this is your maternal uncle's family..." Jiang Li lifted her...
Chapter 307, "I Am Sister's Real Younger Brother!", is the clearest early answer because it turns Zhou Wenshu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with From the certificates and trophies on the wall, it was clear that...