Four Secrets that Naruto didn't know: Secret #2

Secret of the Kyuubi Attack

Akatuki's crime cause the Nine-tailed Demon Fox or Kyuubi came. Kyuubi only come to the place of human whose hearts are evil. When he wags his tails, it can cause tsunami and shattered mountains.

But, Madara Uchiha is a powerful ninja. With his Mangekyo Sharingan, he conquered the Kyuubi. He send Kyuubi to attack Konoha that he hated. That time, Konoha was led by the Fourth Hokage. Fortunately, the Fourth Hokage is also good. He called the God of Death to lift the Kyuubi's soul. Kyuubi's soul is sealed in a baby. That baby is Naruto. Unfortunately, the jutsu to call the God of Death caused the death of the Fourth Hokage.