Question -- the nature of their 'teaming up.' Does it have to be on equal terms, or if, say, the paragon COMPELS the enemy to cooperate, will that satisfy the challenge?

Heyo!

My question is in regards to the necessity for original characters, and the implication public domain characters would have on it.

Essentially, if I have a gorgon named Euryale, whose relation to Perseus's adventure is only mentioned in passing, would she count as a non-original character? The setting is essentially an off-shoot of greek mythology, with some core structural differences and the characters participating in new stories, but with the original myths being accepted as having taken place in the past.

I figured it would pass in the sense that Thor is considered Marvel's original character, though by remaining chronologically closer to the events I worried that I might be pushing the boundary.

If that is not considered acceptable, I'll fall back to making her a generic gorgon with a different name.

Ah, one of the three Gorgons.

As you mentioned, these are essentially public domain characters, and the original authors of their myths are lost to time. There are two rules of noteworthy consideration here.

7. All characters used in your submissions should be of your own devising and creation. You cannot use characters that are not yours. If your submission is based in a franchise setting (such as Harry Potter for example) you may only infer the presence and activities of canonical characters.

The burden of proof rests with you to establish that sufficient original effort was employed in any work you submit.

Euryale could be used, provided you are able to supply sufficient original effort in their depiction to make it clear that they are, as you said 'an offshoot' of the original and thereby not the same.

This applies to any and all public domain characters, including the likes of Peter Pan, Mary Poppins, Alice, etcetera.

This question was insightful enough that I will be posting it and my answer in the discussion subforum (you will remain anonymous of course, but feel free to state otherwise). This may also lead to an eventual revision of some of the rules.