Answer:
This theory ties into the prophecy that entangled Harry Potter's fate with that of Voldemort. The prophecy stated that one must meet his end at the hand of the other. This means that Harry Potter is the only person or thing that can end Voldemort's life. But this also could mean that Voldemort is the only person or thing that can end Harry's life.
Step-by-step explanation:
This is my favorite theory because, it really goes deeper into the plot of the story and movies. This is a really amazing theory, due to the fact that it just really makes sense! It mostly relies on the type of thing that ties in with the fact that harry does get hurt, and almost killed numerous times during the book series. He never actually perishes; so, possibly, only Voldemort has the power to kill him. (hope this helps)