Take a look at this:
https://real-life-villains.fandom.com/wiki/Thread:22157
https://real-life-villains.fandom.com/wiki/Thread:22187
I'm not saying that you should block him, since maybe this is not enough based on wiki's rules, but at least i think that you should keep an eye on him.
Going beyond in our history, this user used to be my friend, but then he showed his true colors, i blocked him on deviantart and now he started to give this messages on here.
For more information, this user has been infinitely blocked on Villains Wiki, The Evil Wiki and some other wiki, and he was once globally blocked after he started to insult admins of some of the aforementioned wikis.<ac_metadata title="About a user."> </ac_metadata>