character tags

I'm uploading a pic from a artist. I don't know how to use tags correctly; there are 5 original characters in the picture, one of them have a common word as NickName (the character is known for the nickname only, no official name were found yet), how do I tag the characters?

He has deviantART account with pictures of his characters, so I think he has copyright over the 5 of them.

Just stick to the tag original. I don't think original characters are typically tagged by name.

OK, thanks. I'll put original for now; I'll see that character_name issue later.

Some possible exceptions:
Many different artists have drawn the character - example: arancia
The artist has drawn a lot of Danbooru-quality pictures of them (let's say 25 as a suggested minimum) - example: chocolat_(sayori)

In general, though, Mysterio has the right of it.

Yeah, we do character tags for original creations sometimes, even when they don't have actual names but it's uncommon.

Hahahaha, thanks jxh2154.

If I find something better, I'll make the character tags (this chars have names AND nick names, hahaha).