He is the only deceased Hokage whose death hasn't been shown. Nidaime Hokage Tobirama Senju- sacrificed himself to allow his students to escape; probably proceeded to to get gang-raped by 20 A's or Bees. Sandaime Hokage Hiruzen Sarutobi- sacrificed himself via Shiki Fujin to seal Oro Yondaime Hokage Minato Namikaze- sacrificed himself via Shiki Dujin to seal Kyuubi in his son. Hashirama is incredibly hyped, beat EMS Madara, Kyuubi, and Kakuzu. I almost don't wanna know how he died if he beat anyone that could come near his power like that.