Most of the Hokage's deaths in Naruto are accounted for: Tobirama Senju died acting as a distraction; Hiruzen Sarutobi perished using the Reaper Death Seal, as did Minato Namikazee. However, there's one Hokage whose end remains shrouded in mystery -- Hashirama Senju.
Nobody knows how the First Hokage died, as neither the anime nor the manga addresses the details of his ultimate fate. Without anything official to go on, fans have been left to speculate on potential causes of death. By using available information about Hashirama, all kinds of theories and conclusions have been formed.
Who Was Hashirama Senju in Naruto?
Hashirama Senju was the leader of the powerful Senju clan, the only one strong enough to rival the Uchiha. He was also co-founder of the Hidden Leaf Village, along with his old frenemy, Madara Uchiha.
The biggest tools in his arsenal were his signature Wood Style Jutsu and his mastery of Sage Jutsu. He later became the first person to hold the title of Hokage, the leader of the village and its best ninja. He's responsible for much of how the modern ninja world functions, including the village system and rank-based assignments. He was a kind, humble and simple man, but he would also kill anyone who threatened him, his clan or his village.
Why Hashirama's Death Is a Mystery
A big issue with discerning the circumstances of Hashirama's death is how powerful he was. In his lifetime, he was the strongest ninja in history, which earned him the title "God of Shinobi." His power wouldn't be surpassed until Naruto's era, which came long after his passing. The only person who ever came close before then was Madara, who was put out of commission by Hashirama himself. For how powerful he was, it's a wonder what or who even could kill him.
What Are the Best Theories About Hashirama's Death?
If Hashirama did somehow die in battle, there are a few ways it could have happened. He could have been taken down by overwhelming numbers like the Third Raikage; if he's really stronger than this Raikage, that would take a force of more than 10,000 shinobi. He might also have been assassinated, but seeing how Kakuzu canonically failed to do that, that seems unlikely, too. He might have been gravely injured by Madara during their final battle, which affected his performance in future fights and cost him his life. He might have performed a noble sacrifice, which would definitely fit with his character. Strong or not, there are plenty of ways to die in a fight.
Many believe Hashirama died a natural death, either from old age or from disease. Such an uneventful death wouldn't have a reason to be shown on-screen, which would explain why it was never covered. It's also comforting to think a man who spent his career in pursuit of peace was allowed to pass on peacefully.
However, natural death is often rebuffed because of the Reanimation Jutsu. This technique apparently brings people back in whatever state they were in at the point of death; this includes their age and whatever clothing they were wearing. Because Hashirama came back looking fairly young and fully armored, it's assumed he died in battle. Again, for how strong he was, that's difficult to believe.
There may be another explanation for Hashirama coming back the way he did. After all, Madara was reanimated in a similar state, but his death is confirmed to be as an old man in robes. It's possible that, under the right circumstances, the user of the Reanimation Jutsu has some control over how subjects are brought back. That would add up, because Hashirama and Madara were brought back by Orochimaru and Kabuto, respectively; one is a scientist and the other his successor. These two would likely try to modify the Reanimation to bring Hashirama and Madara back when they were at their best. That would also explain why Hiruzen was reanimated as an old man; nobody had time to modify his body, so he came back precisely as he died. If this is all true, then the real cause of Hashirama's death would reasonably remain a mystery.
Some have theorized that Hashirama suffered an ironic death due to his healing ability. According to Madara, he had regenerative capabilities, and didn’t even need a hand sign to use it. The same technique, however, might have shortened his lifespan either by making Hashirama reach his Hayflick limit or by creating malignant tumors.
It's also possible that Hashirama died of illness. Like Itachi and Kimimaro, he could have contracted something that eventually cost him his life. Even the God of Shinobi isn't immune to disease.
The real cause of Hashirama's death may never be revealed. For all the things that could kill him, there's a way to say he could survive it. That's what truly makes it so difficult to imagine him dying.
