Originally Posted by
Darthmoe
Here's my theory, it's a long shot!
Okay so if the round circles appear on the user of the technique (3rd hokage) then my theory is that:
Uchiha Madara (or Tobi) manipulated the Demon Fox with their Sharingan and forced the Demon Fox to partake in the death god sealing jutsu. The reason Uchiha Madara/ Tobi did this was not to save the village, but because they knew of no other way to seal / control bijuu's back then. Uchiha Madara / Tobi planned to make the Demon Fox use the sealing technique and somehow go inside of a child that they could later manipulate when the time was right.
The fourth, ofcourse, wanted to get rid of the Demon Fox, but at the same time did not want to help evil people like Madara, so he had a plan. He would give up his own son, Naruto, and told his sensei (Jiraya) and his pupil (Kakashi) that he would trick Madara / Tobi into thinking they could later manipulate / use Naruto and the Nine-Tails to their liking, but in reality he wanted his sensei and pupil to take care of Naruto and never let Madara get his hands on Naruto when the time was right.
And Madara/ Tobi being the evil villain they are, went back on the deal and killed the fourth right after the sealing ritual so that no one would know his true intentions.