Super Senior Member
I agree with Jubeh.
I mean, let's think about it. Pageviews online are disturbingly formulaic. People who poorly draw fanart will most times get more notice, pageviews, and follows than more skilled original artists. I don't mean any barm by saying this, Sunny, but you also work in a niche genre of art. There is such a disgustingly massive stigma against anthropomorphic art that it's difficult to get some people to see past your subject matter and recognize the true talent you have. Because of these factors you can see how a large difference in follower numbers can occur.
I don't think that ignoring this person is the best route. You've obviously tried that method for some time now with no luck. Don't respond to each item of ridicule individually; it just causes bickering on particulars. Instead you could try to formulate a polite letter/message to this person stating your opinions on the matter. Try to iron out your problems.
I'm not saying that this will work, but it is worth a try. Unfortunately this is the Internet, and on the Internet there are people. Some people don't always want to mKe up with you on friendly terms. It's easier to hide behind an avatar and an online persona in order to antagonize others online than it is in real life. Trolls do exist, and they get enjoyment out of what they do.
There once was a person on MT—who I won't disclose—that would troll me a little. It doesn't seem as bad as the situation that you are describing, but it was still clearly an attempt to attack me over art. This person would publicly tell me (and through that, the people that supported me) that I was a fake. They said that for my age, there was no way to have my skill level in art. They would attack me by asking me why I had to lie about how old I am in order to get more attention and praise. I tried explaining to them that I wouldn't lie about silly things like that on the Internet, but I had no luck. Eventually I just had to wait for them to quit the site.
This person on MT wasn't terribly popular socially or in the Artist Alley, so they had no reason to stay forever. The person you are dealing with seems to have a fairly solid backing and fan following, so I can't imagine that they would leave. So here is my suggestion to you if the letter doesn't work: block them. Most art sites like Deviant Art do, in fact, have blocking systems. Even tiny little Manga Revolution had a block system. In the case of DA, a blocked person cannot contact you or even access your profile. Do it privately. Don't mention it to your watchers. Don't tell this person. Just block them and never bother with this person again.