Isobu's previous jinchūriki had been the Fourth Mizukage. The Fourth Mizukage had been a wise ruler, but a Sharingan user had appeared and taken control of him, plunging Kirigakure into tyranny. Dissatisfied with the situation, the Seven Ninja Swordsmen of the Mist, whose original duty had been to protect the Mizukage, had left Kirigakure. Once the Fourth Mizukage had outlived his usefulness, he had lost his life as well.
The jinchūriki before him had been Rin Nohara of Konoha, a ninja from Kakashi's generation. Madara Uchiha had deliberately chosen a time when the Fourth Hokage, Minato Namikaze, was away to target her, forcibly making her Isobu's jinchūriki and placing a restriction on her that prevented her from taking her own life.
Rin Nohara had never possessed the ability to control the terrifying tailed beast power inside her. It had only been a matter of time before she went berserk. With all these factors weighing on her, Rin Nohara had chosen to sacrifice herself, dying to Kakashi's Chidori.
And that very scene had been the trigger for Obito Uchiha's rampage.
One manipulation leading into another-that was also why Chinatsu had not simply stormed into the Akatsuki and dealt with Nagato Uzumaki.
Inside the mindscape, the enormous Isobu watched Chinatsu warily. Although he had felt little attachment to either of his last two jinchūriki, those two incidents alone were enough to make him deeply wary of the owner of those eyes.
"Who exactly are you? Are you working with the people who used me before?!" Isobu stared gravely at Chinatsu as he spoke, though a faint tremor had already crept into his voice.
Isobu: I'm not scared... I'm not a coward!
To Chinatsu, the giant turtle Isobu looked like a cat with its fur standing on end-except this cat's fur was a