So I found some guy on Facebook who is using one of my commissioned pictures as his profile pic. That's nothing new. I've found others who have done the same, messaged them politely to not use my art as their own and they complied.

This dude however...

He has taken so much of my commissioned art, and is apparently claiming my character as his own and in some cases he has claimed the art as his own drawings.

I've never had to deal with something of this magnitude. Does anyone have some suggestions on how to deal with this guy? I'll obviously need a backup in case he refuses to speak to me.