This isn't being hateful or anything, but why do you give a shit about people doing fanart of your characters? All that it means is that some other artist really liked one of your characters and wanted to do it justice themselves. It's not like they'll claim it's their character, they'll credit you.
You're not making a profit off the characters or anything, so there's no loss or negative aspects to people making fanart.
The reality is that the licensing for art on NG does not prevent people from making fan art of your characters. The license only protects the specific image that you uploaded, not the character itself. People are not allowed to modify & distribute that image, or use that image for commercial use. The license does not give you copyright over that character.
Ignoring the case of 10JD, someone making fanart of your work is a cool thing. That means someone is a fan of your work, embrace it don't push it away.
Irrelephant
jack off to hentai
DragonPunch
Anything unrelated to elephants is...OH I GET IT!!! HAHAHA, LOL. Nice name.