User blog comment:B214/Question and Answers/@comment-24098614-20131209074923/@comment-16281343-20131209082602

What B214 said is correct, but some may question about Koneko's 2nd tail appearing or appeared when she used senjutsu.

This inkling of an idea may answer that, since senjutsu has control on one's and other's life force, this caused Koneko's maturity to speed up "temporarily" when used.

Explaining why Koneko's 2nd tail appear when she uses "Nekomata Mode Level 2" and why she "grows up" when she's in "Shirone Mode". Watcha think?