Sad
But he seems to be organised and hell bent on havoc .
But as ToastPwnz mentioned he wont be persistent .
Reasons ....
You have locked the registrations and thereby locking his ability to create new aliases .he has to make maximum havoc with limited resources
He started talking about cyber-bullying .It means he has ran out of ideas (and probably aliases) and he wants more time on that particular alias .
It's just a ploy to throw the mods off-balance .
He and his gang are supposedly seasoned trolls .
But no one is that persistent .
From what I read,the admin is not that active member which is a minus .
That also gave those people (person) some extra boost.
Ask your fellow mods to be persistent against them .And all those legal threats are hog-wash (after reading the local newspaper).When he joined the forums he accepted the terms associated .He will be in bigger trouble in that case.
More ever .The power of a troll lies in his anonymity .If he serves a legal notice (which will be mega idiotic) his whole basis of trolling will be under a threat .And he wont be a Anonymous anymore !!