The fact that Laughing Jack has a dark past and is often associated with fear could be a big hurdle. Reader might struggle with accepting Jack's true nature completely. There could be moments when Jack's powers get out of control, and Reader has to deal with the consequences, which could put a strain on their love. Moreover, their different existences - Jack being a supernatural entity and Reader being human - could lead to difficulties in communication and understanding.
One challenge could be that Laughing Jack is a rather spooky and otherworldly being. Society might not understand their relationship, which could lead to Reader facing isolation. Also, Jack's unpredictable nature might sometimes frighten Reader, causing trust issues in their love.
One day, Reader was walking in a spooky forest. Suddenly, Laughing Jack appeared. At first, Reader was scared, but Jack's strange charm started to grow on them. As days passed, Jack would leave little gifts for Reader. Reader began to look forward to seeing Jack, and a love slowly blossomed between them.
One common theme is the element of mystery. Since Laughing Jack is a rather enigmatic character, fanfictions often explore the mystery surrounding him and how the reader character tries to figure him out. Another theme is the idea of an unlikely connection. Given that Laughing Jack is a rather dark and spooky figure, the idea of him forming a bond with the reader, who is usually portrayed as an ordinary person, is quite interesting.
Privacy would be a huge challenge. Jungkook is a global star, and his every move is watched. So, it would be difficult for them to have normal dates or private moments without being photographed or followed.
One challenge could be Hiei's past. He might have a lot of emotional baggage that could make it difficult for him to fully open up to the reader. Another issue could be his reputation. Others might not approve of the relationship, which could put pressure on them.
One challenge could be misunderstandings. Since Keith might be a complex character, the reader may misinterpret his actions or words. For example, if he's quiet for a while, the reader might think he's losing interest when in fact he's just thinking about something important.
One challenge could be the difference in their lifespans. The vampire is immortal while the reader is mortal, so they would have to face the inevitable separation. Another issue might be the vampire's natural instincts. Even if he loves the reader, he may have to fight his urge to feed on human blood.
One challenge could be Laxus's tough personality. He might have trouble expressing his emotions openly, which could lead to misunderstandings with the reader. For example, the reader might misinterpret his silence as disinterest when in fact he's just shy about showing his feelings.
The reader might face judgment from their own village or people. Kisame has a rather intimidating and feared reputation. People might not understand why the reader would be with someone like him, which could lead to the reader being ostracized. Also, Kisame's own past actions and the blood on his hands from his ninja duties could be a moral dilemma for the reader, making it hard for them to fully embrace the relationship.
One challenge could be Sasuke's past. His thirst for revenge might make it difficult for him to fully open up to Reader at first. He has been through a lot of pain and trauma, and it could take time for him to trust Reader completely.
One challenge could be Zero's past. If he has some dark secrets or a troubled history, it might make the reader hesitant at times. For example, if he has a history of pushing people away due to past betrayals, the reader would have to work hard to break through those barriers.