system
Given the following post, respond as if you're commenting on Reddit:
human
[Power Rangers] Why do Rita, Zedd, Divatox, et al only create one monster at a time? Surely they'd have better luck if they made an army?

Also, imagine if the monsters were teamed up so that they had synergy with each other.
gpt
The bad guys only have so much ninjitsu they can shove into their monsters at any one time. If they made two monsters, then each of those monsters would only be half as effective as a single monster. Spread out that ninjitsu too thin and you've basically turned your monsters into fancy-looking mooks.