Strength, physical, and magic attacks are high. There is a 1/2 chance of the monster using Haymaker. When HP is low, it also releases Blast Punch, which delays turns.
Defender Z is an enemy from Final Fantasy X. It is an ancient machina built by Bevelle for use in the Machina War 1000 years ago left wandering the ruins of Zanarkand. They are also encountered in pairs in the Omega Ruins.
The easiest way to defeat these monsters is to hit them with Provoke, which causes them to only hit that character with Blast Punch. Once they have been provoked, they should pose little threat and can easily be defeated. Unlike Defender X, the Black Magic Demi is effective and able to do 9,999 damage due to Defender Z's high hit point total, ideally Doublecast to deal nearly 20,000 damage each time.
The Japanese name for the enemy terms it as "Zero-type". This draw upon the East Asian production model variant identifier suffix (式, shiki?) or "-Type", that began to saw use in the 1920s in Japanese and Chinese manufacturing, particularly in the military industries.