Built in Comment System

Is there a theme that offers / provides a built in comment system that does not rely on a third party?
If so, please let me know.

I’m looking for an option whereof the IP and userdata is anonymized or not present at all.

No, theme’s can’t add that sort of functionality to Ghost. If you need a commenting system you need to use a third-party service.

There are many topics on the forum discussing various options so I’ll close this to avoid splitting discussion further.