What must a grandmaster do to earn the right to reincarnate?


Near the climax of the movie, the grandmaster gives up his right to
reincarnate to Kumatetsu. This right allows Kumatetsu to be reborn as a God.
Later, we see that the grandmaster can no longer reincarnate into the god of
decisiveness as he had finally chosen earlier.

I originally thought that all you had to do to reincarnate was become the
grandmaster, but that would make becoming a god too easy. As you could keep
the line moving pretty quickly if everyone became a god as soon as they became
grandmaster.

So it brings up the question: once you become a grandmaster, what must you do
to earn the right to reincarnate as a god?

