Someone with the title of 'visitor' is sending me harassing messages, how do I prevent this? He does not appear to be registered (now he is a 'member', it said 'visitor' earlier). Either 1) anyone can message me without an account, which is dumb or; 2) he works for the forum.

Either one is a pretty good case for deleting this account and writing this site off as unsafe and unsecure.
This message was last edited by admin, as it was in need of a minor tweak, at 13:14, Tue 26 Jan 2021.

'Visitors' are not a thing. You missed 3)Someone hacked an admin account.

The title of the thread changed so that seems likely.

As far as unsafe, you shouldn't have any compromising data on this site.
This message was last updated by admin, as it was in need of a minor tweak, at 13:14, Tue 26 Jan 2021.

Inform the mods. They will be able to kick / ban anyone harassing you.
This message was last updated by admin, as it was in need of a minor tweak, at 13:14, Tue 26 Jan 2021.

I sent an rmail to them.
This message was last updated by admin, as it was in need of a minor tweak, at 13:15, Tue 26 Jan 2021.

That's a level of petty I wasn't prepared for this morning ... here's hoping the Chamber of Lost Souls sees an update.  :)
This message was last updated by admin, as it was in need of a minor tweak, at 13:15, Tue 26 Jan 2021.

That account has now been banned.  Some people think it's funny to create a dummy account (the visitor/member issue occurs twixt verification) and harass players, but it only takes us a few clicks to ban them.  Most instances we've seen involve somebody who has an axe to grind escalating an in-game dispute, and most times the original account has already been banned for such behaviour already.

Petty doesn't even begin to cover it.  Not the sort of person you'd ever invite to your house in the first place, let alone a second time.

Just keep reporting any such contacts to the moderators by rMail and we'll take care of it.
This message was last updated by admin, as it was in need of a minor tweak, at 13:15, Tue 26 Jan 2021.

Private messages from non-players have "(visitor) Bob Smith" or similar as the author's name, the bit after "visitor" is the important part.  Opening the thread also shows the author's name.  Either way the member name is plainly visible to you (and to me which is why that person now has their access suspended).

As I'm writing this I can see you've updated the thread topic to reveal the member's name (which I'll shortly edit out) so you've clearly spotting your oversight, though this hasn't make you change your accusatory and inflammatory comments.

In future please rMail the details to moderators and admin so we can investigate, that's the better way to handle these things rather than airing dirty laundry and offering incorrect conclusions.  Also don't feed the troll.