If anyone two people are responsible for the entirety of Naruto's story, it would probably be Obito and Orochimaru.
Obito pursuaded Nagato to set up the modern Akatsuki - the main antagonist group for most of Part 2. Without Obito, Madara would not have found a worthy heir to continue his plans since how many emotional Uchihas wander into a cave during a war? Plus, Minato would probably still be alive.
Orochimaru is pretty self explanatory. Instead of Sasuke running away with the Sound 4 (they prob would not even be formed!?), he would have been stopped.
Now I would say Naruto is the cause of Naruto's story but that's a lame answer.
Obito pursuaded Nagato to set up the modern Akatsuki - the main antagonist group for most of Part 2. Without Obito, Madara would not have found a worthy heir to continue his plans since how many emotional Uchihas wander into a cave during a war? Plus, Minato would probably still be alive.
Orochimaru is pretty self explanatory. Instead of Sasuke running away with the Sound 4 (they prob would not even be formed!?), he would have been stopped.
Now I would say Naruto is the cause of Naruto's story but that's a lame answer.