Guide to Pre-Existing Character Roleplaying

[Polyedit2000]

There's another question:  When should I use pre-existing characters?  Part of that is based on the GM's preference (I'm okay with it), but beyond that, it's more than seeing if the setting is okay.

With Pre-Existing Settings, there are two extreme cases.  A) The GM limits the cast to pre-existing characters (ie WOOHP Spies only) or B) the GM limits the use of pre-existing characters to themselves.  In the latter case, this may be because the GM wants them solely as quest givers or want players to be a "new season".  There may be exceptions for "returning characters" if the GM allows.

Then there is a "Isekai" factor, or placing these characters from cartoons and anime into this setting you have.  As Flashlight points out, some characters are human-like, the Total Drama girls having a skillset comparable to your own OC with the exception that they appeared on a TV show.  Others, like Shantae, are less likely to appear in a modern setting, though aliens like Lum might technically exist in a modern setting...

Toons, strangely enough, are an example that can exist in a modern setting in two ways thanks to existing media:
-Toon Town, where Toons and Humans coexist.  Done with Roger Rabbit, Looney Toons, and Animaniacs.
-Television, where a Toon comes into the Human world.  Done with Rocky and Bullwinkle and Fat Albert.

There are other options, but the Toons demonstrate that, with some backstory of how they got there, it's possible to use any character. Though not all "Toon Invasion" is necessary to include cartoon characters. In the case of Fairly Odd Parents, they did bring characters into and out of comics/television and wished the world as a comic book, but they also had some live action adaptations to show that "toons" can exist in the real world as is.