Well there is one Australian schizo who spams boards, one of his main regular activity is spamming ausneets, and recently he does it with freekukuku, but he does his performance elsewhere too like baaa2, or fsschan, or agatha2 and he did other boards in the past years.
It's hard to pinpoint what he does on boards with language we not familiar with, especially if it is written in different writing systems.
Posters should ignore and don't interact with him in general, that also helps separating attackers from regular users. The one who posts over and over but gets no replies might just spamming. Yeah I know he can reply to himself. But ignoring is good policy because users don't get riled up by his shenanigans that way and he doesn't get any attention.
Users also should volunteer, register a username, talk to BO and as for a BV position.
Regular users generally recognize each other on these boards they use for years now, frankly all of em could volunteer and take care of the issue. Native speakers can filter out bs posts that just take space easier. He uses online translator services obviously.
I issued a ban on a post, just before I started to write. He'll switch IP, because that's what he does every time.