User blog comment:AnonymousAK/Demon's Royale/@comment-25121709-20140715151833/@comment-24066070-20140715201038

Zoldeo is a special case, since he just inhabits the body of another person/being and he is apparently forced out of said body when he sustains a serious injury. You can "return" all these chars (Zancrow, Azuma, Jackal,..) to an unharmed state without affecting the abilities of another char in the series, but this does not work for the Zoldeo from the Tenroujima Arc since that would "remove" a Key from Lucy if you do such a thing.

If you want all chars to return to their "default" form before they were defeated, then return Zoldeo to his real body from before he broke the taboo. After all, he did not use any of Caprico's abilities during the Tenroujima Arc, so he doesn't get noticeably weaker.

There are still quite some people who think Caprico was a member of the Seven Kin, while it was actually Zoldeo. A real life friend of mine thinks Lucy is a dumbass for not using Caprico in the GMG to suppress the powers of her opponents and even after explaining that Human Subordination belongs to Zoldeo and not Caprico he still doesn't get it.