is it possible to change lfsworld username?

Yep, it is _possible_, but ScaViEr won't do it as it takes too much time (something like that)

It's not possible, It probably could be done, but Victor will not honour said request, and as it says on the register page, is that your name is yours forever.

But when that is said, that is only your account name, you can change your nickname in game (that everyone else will see) to whatever you want, and you can change that as many times you like. So don`t be frustrated if you picked a account name you didn`t like, just take a nickname you want