we should team up
/waggle waggle
@kurapikasuki: I think a lot of your rough luck with "fans" over the years somewhat stems from the fact that you established your fanbase at DeviantArt. Yes, the website works for what it does, but it's definitely been a slow decline into chaos over the past several years :/ ( I finally just went "fuck it" when they did that major overhaul with the logo and the CORE program and shit... next to the fact that I had ZERO success on DA, as most of the views were - and still are - going towards furry art, Sonic art, pony art, Sakimi-chan, and the like, plus the community was toxic, and I just didn't see the effort in posting to it anymore when I had more success on platforms like Tumblr, Tapastic, Instagram, etc.).
Along with that, it seems like you fell into the "sunk cost fallacy" trap - despite his clear abuse, he was still a fan of another comic you made, so you let it slide for as long as you could. Let's compare the webcomic community to, say, a cafe (and I know that most of our readers aren't paying to read our stuff, but bear with me here lol) - there's one abusive customer who's in every day, constantly belittling the staff as well as other customers, and just makes it an overall negative atmosphere for everyone in the cafe. But this guy comes in every day, spends up to $10 a day at the store on average.
Should his behavior be tolerated?
Absolutely not.
Even more so in the webcomic situation - he's not paying to read your work, and you don't have any actual, positive incentive to let him continue that kind of abusive behavior, so it's best just to cut ties right there and let him suffer the consequences. Letting him continue just means he knows he can get away with it - which would fuel the fire even more for when you do block him, as he would come back over and over again, knowing that you wouldn't be able to do anything (maybe even if you could), and even go so far as to bring other innocent bystanders into the mix (some not even related to you in the slightest).
I know it's in the past now so my advice doesn't mean much, but this goes for anyone who deals with abusive readers - they are not obligated to read your work if they are just going to trash you and everyone around you. Reading your work is a privilege, not a right - and if they abuse that, and if you have the power to block them/ban them/etc. then use that power to its potential and protect not only your own reputation and comic, but your community and their online safety as well.