Thanks for googling that for me Meh! anyway you messed up my post, lol why do I feel like I and fluffyboy were the only people who posted logical posts..
The reason of Hashi's death was never mentioned in the manga, but considering his appearance when Oro first revived him through Edo Tensei, he's still young so I guess he died because of some complications from using his techniques... he pretty much died from natural death since he's unbeatable in battle. no one could kill him during his prime.