I have been occasionally following what's been happening on your wiki since they decided to come here and bother you here. I have some advice on how you can more effectively deal with them, from one admin to another.
If a similar user name shows up right after you block one, it's likely the same person. Block them, then undo or delete the edits. Looking through the block log, I see at least a dozen similarly-named accounts.
When you issue a block, put a check in all options except "Watch this user's user and talk pages". That way, you won't have to be bothered if someone else comes in and changes the talk pages later.
Stop putting personal comments in when you set a block. Use matter-of-fact reasons like "harassment and vandalism", rather than the ones you have, such as "Putrid, cancerous abomination".
If you haven't already, you might want to have anonymous editing disabled, as recommended here. It won't stop everything that's happening, but it will slow it down a little.
They're being obvious in their vandalism and harassment, so don't ask them why they're doing it. Ignore their messages to you and just block them. When you talk to them, it gives them attention that they are looking for and lets them know that they should keep at it so that it will continue to bother you. Talking to them is "feeding the troll".
Delete their user talk and profile pages. That way, there will be even less attention given to them.
Get the VSTF involved. They have more resouces available to deal with vandalism.