if he died for the same disease which affected itachi and kimimaro,he wouldn't be special any longer. I know itachi and kimimaro might have had different diseases,but hashirama mustn't have died for such a common cause,imo.
Hashirama certainly didn't die of "old age" or "natural causes". At most he would have probably been in like his 50's when Tobirama died and Hiruzen became Sandaime Hokage. I doubt we will ever find out how he died, and if we do its probably going to have to be related to some disease.
btw,the fight against madara is going to an end,I really hope someone will reveal how he killed soon. yet,the fact Madara hasn't asked yet who had killed him makes me think about 2 possibilities: 1)madara lived more than hashirama and already knows who killed him ; 2) hashirama died for natural causes. but both of them requires him to ask the others,maybe he died for natural causes and he knows that
I get the impression that Gedo Mazo once belonged to Hashirama, and now that it is contracted to Tobi I get impression that he, Madara and Zetsu are responsible for Shodaime Hokage's demise. That or he took himself out using a forbidden jutsu.
I tghink hasirama simply died of natural causes... he was a "fairytale" shinobi ( according to madara ) - he was mentioned on the same level as reduku sennin... as them both being fairytales and ninja that couldnt posibly be so strong... anyways for that fact i find it hard to believe that he was either killed or died of a disease... tsunade has the ultimate regeneration jutsu and even she admitted that using it too many times shortens her lifespan.... Hashirama Senju was praised by madara for being able to use the same ultimate healing but without the use of any seals... my guess is that it has the same life-shortening effect if used too many times... and considering the epic battles that hasirama probably was forced to use this healing from i guess his body just died of pre-mature old age...
so if for example using that kind of healing took lets say 4 years off your life everytime you use it and it was mentioned that the senju and uchiha clans clashed many times and madara and hashirama faught many times ... if he used that jutsu lets say 10 times in the course of his life he would have shortened his life by 40 years... so if he was suppose to live naturally to lets say the age of 80 he would then died at around the age of 40
I think after his fight with Madara he has severe wounds and injuries.And after that his body couldn't stand it anymore maybe right after his fight with Madara maybe after a year but I think Madara vs. Hashirama is costed both of their lives.
Hashirama accidently used a create a enormous maze made of gigantic trees and forests no jutsu , get lost in the maze and died from hunger cuz he couldnt find the exit
He could heal himself. He was surrounded by water in The Valley of The End's waterfalls.
He is seen with Team Tobirama in their team photo.
He had the time to hand other villages the other Bijuu's. I dont have time to list all, but he did loads of stuff while Hokage so him dying just after the fight isnt possible.
I don't see why it matters how he died he's a DEAD character. And has been since the series started.....IMO the Narutoverse time is off a bit..Due to flashbacks and characters age it's kinda hard to map out Naruto's history accurately i don't believe everything would juss mesh together..But Senju Hashirama simply died when he was young, The third hokage was still a boy when he died....His brother died a few years later..As he gave Sarutobi the mantle of Hokage when he was seemingly early 20's............How and Who are questions that we really don't need to be answered. 2nd Hokage was killed by 20 Special Anbu Cloud Unit....The 3rd Raikage foguth several thousand Shinobi for a day n night i think it's numerous days n nights.....Stop wasting brain cells over who killed the man..He's died period