Advice: Patenting a Character/Species

[mochacorgi.livejournal.com]

Hello all!

I am working on a comic currently, however, someone, who will remain nameless, is deliberately Stealing and selling the Main species of the world as a "closed species"

I have proof that the species is originally mine, not his, in creation (with a 4 year old, unmodified/updated ref)
I had relations with this person formerly, so this is all being done to spite me

My species is not "closed" however him selling them as closed is becoming a problem for my comic (I sell the species for cameos in said comic, but anyone can make one)

How would I go about protecting the species?

EDIT

I appreciate all the Advice. As of currently I have been working on a restraining order.

However. I noticed a major string of hidden comments on them trying to sell the species, and I'm not pointing fingers, but if it was one of you, PLEASE DON'T CONFRONT THEM. I didn't mention names for a reason and every time someone does something like that they call my poor father and scream at him (because I changed my number twice so they couldn't find me)

Thank you :C