The Four-Tails (translating for "Yonbi") is one of the ten classes of the tailed beasts.
Four-Tails are very prideful tailed beasts, as they detests being called "Four-Tails" and boasts about their lineage. It uses 'ore' when referring to themselves.
Some Four-Tails also hated humans, due to the fact that humans have enslaved them, and believes that they are more intelligent than humans. However, when talking about the Sage of the Six Paths, they showed him great respect. Other Four-Tails are able to overlook some of the humans' cruelity as they have great intelligenes, they can also find inner peace.
They also seems to have taken a liking to some humans and other jinchuriki, as it was moved by their actions for their determination to save them from being controlled by the Akatsuki and would even grant them some of their chakra before being sealed away.
Four-Tails have the ability to simultaneously use two of the main chakra natures and mixture those two into an advanded duo nature. Four-Tails are able to create Tailed Beast Bomb. Four-Tails are very strong as they are able to lift and toss any Eight-Tails.