For the latest release (with Nythera and chaos)? The forge would be in Frozen Northlands
(/join northlands).

You can do /join northlands or just click on the map and there must be a ice land right
above click there then click on guwio village afterward talk to the man who his above
nythera.

you just press map(that is the icon at the bottom like the world).you click on the dragons
horn(because it is a dragon).then click on the red button what says guwio village.Or if
you want it with no people only you put in:/join northlands-9000.It will need to be 9000
because if you put 9999 it will turn into something like 1903 or a different number.