That's what the Akatsuki were doing all those years, gathering the tailed beasts. That story about them all being combined into the Juubi, i dunno if you heard about it, but it's true.

But they only had seven- I still have Kurama, and Octopops- he's the Eight-tails Jinchuuriki- still has his, but they got the chakra from some other place?

[If only there was someone else here who could do all this explaining stuff. He is like, the worst at it.]