K'un, the hexagram of Sigma Uchiha, has stated that in order to perfectly manifest the Tailed Beast Chakra, one must have a unique source of chakra of their own. Those who have fully mastered the chakra of their beast, can attain the power of the tailed beast. Naidō, the original spirit guide of Sigma noted that this power is only exclusive to those that have also achieved the control over Hagoromo's chakra. Those that have truly gained complete control over this kind of chakra, are on an entirely different level. Thus, one can gain the classification as a "tailed beast". This has been the case for two specific individuals, Sigma and his father Sannoto Senju, who gained access through his own means.