Kurama is his name. Widely known as the strongest of the nine tailed beasts, even with half its strength, kyuubi has a great deal of brute force. Reputedly able to raise tsunamis and destroy entire city blocks with just a single swipe of one tail.
He possesses massive reserves of powerful chakra and can accumulate huge amounts shortly after using up most of his own.
Uniquely able to sense negative emotions, as well as natural energy, from great distances he can accumulate both and transfer them to his host to create natural energy.
A fox with opposable thumbs, Kurama is a remarkably cunning leader who can formulate strategies in the midst of battle. In addition, he has an advanced understanding of nuclear physics, particularly the nuclear fusion that occurs within the Sun.