Mount Shumisen was where Hiruko set up his base of operation in the third Shippūden movie. On the way there, there are four gates, the first three guarded by a one of Hiruko's subordinates. On top of the mountain was Hiruko's fortress, where he had all his kekkei genkai-carrying victims crucified.
Mount Shumisen is one of the three requirements for Hiruko's Chimera Technique to completely absorb all five of Hiruko's victims, "earth", and the mountain being close to the solar eclipse, which is another requirement, "heaven". The five human sacrifices, "human", would allow Hiruko to become immortal and perfect.
When Naruto Uzumaki prevented Hiruko from completing the ritual of absorbing Kakashi Hatake, Hiruko released a massive wave of chakra to destroy his own fortress, and their ensuing battle caused much of the mountain to crumble.