Growth
When Kurama had first been sealed within Uzumaki Naruto he had been angry beyond reason. Angry at the Fourth Hokage who had sealed him inside a child. Angry at the loss of his short taste of freedom. Angry at the man who had caused the death of his previous Jinchuuriki, making his new vessel necessary.
Eventually he settled down into being sealed again, and his rage faded a little, he no longer wished for the death of his Jinchuuriki. Instead he wished for the deaths of the people of Konoha. Previously his Jinchuuriki had been treated with dignity and respect, as he would expect for a person giving their lives to save theirs. This new Jinchuuriki was treated like scum, despite being a mere child, who knew nothing of his fate, despite being the child of two people who gave their lives for this village.
And as his Jinchuuriki grew, he was forced to watch his abuse. This was what made him maddest of all, that people could not look past their own blind hatred to see this kid for who he was, not as a weapon. To see the potential Uzumaki Naruto had.
It was this anger than made Kurama push the child to become stronger. He put blocks in his path at every opportunity to force him to realise his true strength and gain the respect of Konoha, and only then did he let him access Kurama's full strength.
And now as he was torn from Naruto he had to watch as all the boy's struggles and triumphs went down the drain, all the progress he had made, lost. The only chance he had was that Tanuki brat.
Kurama just hoped Gaara would be fast enough.
Chapter 661, Goddamn Kishi, you barely kill anyone for an entire arc then bam you almost kill TWO characters? I mean yeah they have plot armour thicker than the great wall of china but, seriously?
Also, thankyou to Lucio Betablake for these last two prompts! I'm pretty sure these were not what they expected :)