BLITZ TOURNAMENT

P.S. The winner will, of course, be determined by the number of Z.

Well, I don't know... it seems to me that the winner will be determined by the number of N!
N is the number of skeletons in the army.
So, the closer the number N is to the number Z, the higher the chances of winning. :D

Added 6 minutes later

P.S. Let the number of skeletons be X, no, that's too few - better Y. :)

Correct:
Let the number of skeletons be X, no, X is too small - better let there be Y skeletons.

:D