I know that this is a necessary weasel, but the whole "Dark Kingdom turning people into Youma" falls flat when you start to think about it.
Obviously, Jadeite did not have this ability and he relied on Youma that could disguise for his infiltration schemes. Nephrite was able to possess individuals with a Youma, but he had to make physical contact with the individual first and the Youma still emerged separate from the victim.
Then we get to to Zoisite and the Rainbow Crystal carriers. This does seem to work with internal logic as this is something specific to these seven individuals who are monsters reborn as humans, especially when you consider that our heroes are revealed to have a similar backstory, being reincarnated as people from their previous lives from another kingdom.
Then Zoisite decides to "modify" the Black Crystal to turn
any regular human into a monster.
This is where the magic starts being a stretch. In all the cases of transformation or possession, it involves something that was already there, either implanting a Youma or essentially restoring the Youma's soul. By contrast, what makes normal people normal people is that we can't just change into monsters. If this is the power of the dark energy, then this changes the Dark Kingdom from being a parasitic invader to possibly eliminating the human species if it ever got enough energy to enable these transformations en masse. Why wasn't this specific threat of a "Youma World" ever brought up to highlight the increased stakes, for instance?
Aside from that though, is the idea that if Zoisite has the ability to change people into monsters with the Black Crystal, why only use it for one episode and for one victim, especially when that mission was a success despite not being able to use the intended target? I would think turning a person into a monster would at least make another temporary lackey and to fight against the heroes would be a smart move. Imagine if when Zoisite dressed as Sailor Moon, instead of merely honey trapping him, Zoisite could have had a human-turned monster waiting, and with the real Sailor Moon trapped, there would be no way of restoring the victim.
Despite Zoisite changing the Black Crystal , the only other time it was shown was when Evil Prince Endymion had it to try to capture the Shadow Warriors again. While it can be inferred this is the method that Kunzite used to change people into Youma, this item is a critically underused tool. And if this is not the method that Kunzite used to turn people into Youma (and there's evidence that it's not, as Kunzite's Youma could talk normally compared to only one sentence for Akan...and Kunzite created more Youma after the Black Crystal was destroyed ), why didn't he do like his PGSM counterpart and attempt to turn Sailor Moon into a Youma? Even if the girls are immune, why didn't he start converting people before he was named co-COO or whatever by going out an converting people to boost their numbers. Even if he's limited to one-shots, he could have converted a group like he did with the women at the salon while the other generals were active. That way you have guerilla Youma out there. Surely Queen Beryl wouldn't have minded if he had created allies who would be spies for the Dark Kingdom while the other schemes are going on.
The sad thing is I
love this trope but in the anime it just comes off as...lazy.
Perhaps they were reborn. It would be funny if those two got reincarnated into good humans...but like Hotaru had to start out as being babies and were magically sent away because of it. Of course that would mean they would just reach their respective ages right about now, 30 years later.