Whenever Obito infiltrated Konoha, he would visit the Memorial Garden to mourn Nohara Rin. That place held his most beautiful memories.
Rin's gravestone had become the symbol of all his pain. Every time he stood before it, the hatred and anguish in his heart grew harder to suppress. He hated Konoha, hated Namikaze Minato, hated everyone who had failed to save Rin.
During one infiltration of the Memorial Garden, Obito hid in the shadows and saw Kakashi mourning Rin as well.
They had once been teammates, yet they had now set foot on completely different paths. From the shadows, Obito heard Kakashi muttering to himself, mentioning that his teacher's wife, Uzumaki Kushina, was pregnant.
From Kakashi's words, Obito learned that Uzumaki Kushina, the Nine-Tails' jinchuriki, would give birth soon—a time when she would be at her weakest.
At the thought of Namikaze Minato, the anger and hatred in his heart flared up once more.
He hated Minato. He had clearly possessed the ability to save both him and Rin, yet he had not acted, resulting in Rin's death.
He wanted revenge on Minato, to make him experience the pain of losing someone dear to him.
Obito decided that, at the moment Kushina gave birth, when she was at her weakest, he would release the Nine-Tails and drive Konoha toward destruction.
He believed that once the Nine-Tails was released, Konoha would inevitably descend into chaos, and the other villages of the Ninja World would seize the opportunity to attack it.
Not only would this avenge him against Namikaze Minato, it would further weaken Konoha's combat strength and create an opportunity to capture the tailed beasts and carry out the Eye of the Moon Plan.
When Obito told Black Zetsu of this plan, Black Zetsu voiced strong opposition.
Black Zetsu believed they