Board Thread:Versus Debates/@comment-31337598-20180202202814/@comment-734582-20180204172305

Lorenzo.r.2nd wrote: 1st, hiruzen was said to have been the strongest kage ever, but when minato came in, HE was stated as such. Keep in mind that when people are dead, their strength is irrelevant. Hashirama may have been the strongest in his life, but once dead Hiruzen was the strongest, and once he became Kage Minato was the strongest. Once Minato died, Hiruzen was once more the strogest.

It's similar to how Itachi was called Invincible even though Madara or Hashirama would stomp him like a bug: they were dead, and dead people can't fight.