Added to all LaTale forums. For non-specific ones, just don't add a prefix at all.
As for threads already made, you can't change it, unless you can find a Moderator that would want to coordinate with someone that knows which threads should be changed to what prefix.
Name Changes: Please check if usernames are available before requesting by typing this in your address bar:
Steam Account - doobie15
Battle.net Account - Theosis#1417
Guild Wars 2 IGN - Theosis.8752