Board Thread:Theories and Speculation/@comment-5936871-20160708064710/@comment-734582-20160708080445

When Hashirama and Madara stand atop the future Hokage Monument, it is already announced that the Shimura and Sarutobi clan is joining their alliance.

Therefore, Hiruzen is not a Senju.

More specifically however, the Senju have died out but passed on their beliefs and teachings, and in the ideological battle between "the greater good" (senju) and "individual power" (Uchiha) the majority of the village falls into Category 1.

Simply put, the Hokage have continued the Senju's teachings.