Unfortunately, the forum back up is all or nothing. I would have had to reset the entire forum back a week in order to get the threads back. Too much would have been lost so I started rebuilding the missing threads.
Any of the work you put in on Nameless, Vice, Vanessa, Seth, Leona, K', Shingo, Kusanagi or Kyo-1 would have been posted on the Wiki so they would still be intact. I'm putting in more effort to get the character threads updated to the Wiki as it's a better back up than the forum back up.
I'm very, very sorry this happened and have a system in place which will prevent this from happening again.