Ask The Tropers

It's not YMMV because it's an objective thing in the fan works themselves, and looking at the related pages many of them indeed seem to be fanworks. That said, I am seeing some others that could use a second look.

At its core, the trope is objective. Original Characters that made to fill-in obvious gap in the cast's theme motif.

However, many "examples" are advice instead of example. And these advice is often more of "this show's motif is so board you can easily make one" instead of "fill-in the gap". And that's real problem IMO.

There was a discussion about this topic, where one of the possibilities was to turn it into a YMMV subtrope of Fanfic Fuel (since it's currently used as "original character fuel"). Another possibility was to make all of the examples be about specific fics that use Sailor Earth characters, rather than works that inspire many such fics.

I prefer the first of these, since some works inspire loads of OCs without those characters being used in fanfiction. I know this, because over on Reddit, I run a pretty active community where people make up loads of JoJo's Bizarre Adventure characters, just for the sake of inventing characters rather than to use them in a story.

^^^ Problem is, there's many instances of it being listed on an original work as if it were a trope. Some examples:

PuellaMagiMadokaMagica.Tropes N To S:

• Sailor Earth: Very common in fanfic; easiest is creating new magical girls; but also Kyubey variants with personalities named "Prefix"-bey are often villains or characters since Kyubey's personality is really tricky to do correctly.

Unnatural History:

• Sailor Earth: When they're not writing Jasper/Henry slash, fanfic authors enjoy pairing up the already hinted Maggie/Jasper relationship, and writing in an OC (usually very well-travelled as well) to act as a Love Interest to Henry. These can stray into Mary Sue territory.

Pikmin:

• Sailor Earth: Good lord, the sheer amount of fanon Pikmin created on a daily basis rivals the number of Pikmin you can grow throughout a playthrough. It helps that the Pikmin have a pretty blank template to go off of. Just pick a color that hasn't been made official yet, give it some unique body feature no other Pikmin has, and then give it any power or immunity you want.

Mixels:

• Sailor Earth: Many fans have created their own tribes based around different elements and themes. Most of the time, they'll have female members, since the series lacks any. Notably, LEGO encourages the fans to design their own creations with the characters.

Wreck-It Ralph:

• Sailor Earth: Plenty of fans of the movie have come up with their own Sugar Rush racers.

"Work has a pattern to its characters that simplifies creation of Original Characters" and "fan work has Original Character that follows pattern established in the original work" may be just different perspectives of the same phenomenon, but the distinction is still important because one is about the original work, and one is about the fan work.

Sailor Earth as it currently stands just sorta mashes them together.

This trope should be listed on the fan work, not the original work. Any "use" on the original work is by definition misuse.

It's not YMMV because it should only go under the specific fanworks where they appear (the Sailor Earth page is an expiation). O.C. Stand-in had the same problem. Examples under the official/original works should be cut and/or moved to the Sailor Earth page or the specific works if applicable.

Draco in Leather Pants and Ron the Death Eater had the same debate over if they applied to the original or fanwork. I got approval to remove them from the official works here and here, replacing with Misaimed Fandom or Never Live It Down if applicable. That's more president for cutting Sailor Earth examples from the official/original works.

Also, the examples on the main work pages that were posted above are all general examples, so that's another reason to cut them.