I believe that every stories were connected, no matter how far, different, bazaar and strange. If we somehow write a right bridges between different worlds, nothing is impossible!

Just like stars connected to make a divining constellations, stories and novels were all connected due for unknown reasons. But that's what makes a story even better. A novel consist of two stories, remembered as their past lives, As they journey through different worlds. So if you a fan of one story and the other, it's okay to combine such ideas as your fantasized characters and heroes shall embarks on a new adventures you're wrote. 

Remember, great stories came from your great ideas and imaginations. You just need to write a plot bridges that collide two characters from different novels. 

I know this tip will make complicated things worse, but no matter what or where the stories they've been, their paths will be woven together by fate.

Thank you!