Reili
What if creation is only using sould of criminals? It wouldn’t be to different from shiro using her lantern to toture dark souls, or when she killed those only with dark souls and saved the rest. It would jusg be not killing them, and using the dark souls to emporer herself. But still, thise souls deserve to become reincarnated. Even if they were dark, it doesn’t mean they would be dark in their next lives. Also, can shiro use her reincarnation spell to set thise sould into the oath and then drag them back out again with their memories kinda like she did with the subjects of that one queen whose body was taken over by 3 gods? If she dies that then she can ask those souls what the side kf creation is like. It might be helpful. Anyways, at least if the first born kf creation is evil, it would make it easier for shiro to kill her and what i would asume to be absorb her and her powers.