Does naruto's might guy die

Answer 1

Not yet, but however it is highly possible that he will die against Kisame.

Opening the seventh gate is already life-threatening, and it wont be enough to defeat Kisame, even if he is weakened. If it comes down to it, Gai will open the eighth gate, too combat Kisame. The results, of course, will be death.

It will turn out like how Asuma died, just to give his team some screen time. Although, this is all just speculation.