All you need to add someone to your universal friend's list is the @handle - log into your account on the web to figure out what it is. You will see this person online with any character they play, followed by their @handle, once you've added them.
Kethron - @ryaul
Verdigris - @HalliKenafin
Harka - @Harkathemad
RemyCC - @JeremyCC
Drafin - @Drafin
BurningNebula - @Celdia