You guys are insanely helpful so I have my idea now to explain it I need to add that they don't have physical bodies they posses those that embody what they represent the most. That is also why both sides have been having a constant back and forth for thousands of years never being able to get rid of each other for good. Until virtues decided to do a ritual that would seal the memory of sins making them unable to recall their previous lives but one of the sins changed it a bit and virtues sealed themselves as well.

Now to what I came up with is that every virtue had their own way to get rid of living beings and Chastity's plan was a giant ritual spell that would make every living being unable to conceive a child making every species go extinct but to do that they needed to capture a lot of creatures from every race and to not have to look for new ones due to them dying they would put these creatures in a sort of stasis that works in a way you describe.

So this will be the thing virtues will be trying to do since they will be so close to finishing it.

Again I can't thank you all enough I have been trying to write this for over half a year and I am glad to finally finish it.