[@Lmpkio]

Well, Usagi (funny for a wolf to be named rabbit, BTW) is much better than Lilith though her power is still a bit undefined, mainly because of that mana thing that was totally unnecessary. Indeed, you can't have an unlimited number of resurrections to do, but a more understandable limitation would be better. Like, being limited to do it only once per hour, and not being able to bring back people that died more than 12 hours ago. Our singing like this.

Now for yours and [@Ashifili]'s question. Nothing would happen and she would depend her power uselessly. The reason is that someone's soul don't kill them directly, but instead renders a human comatose, and most Youkai (mostly non humanoid, with a few exceptions) have soul and body joined as a single thing, so Rui-ling's power outright kills them and they can't be revived by any known means.

Also, it's impossible to create new souls. You can build a facsimile using some forbidden arcane methods, but still such a "soul" would not be the real deal in many ways.