Known, active characters are at http://xivsoul.com/ but take that list with a grain of salt - that's the total character count, not the number of concurrent logins, which is Balmung's problem. Lamia has had a short queue since launch, but nowhere near Balmung's problems, because most of our player population is still in sprout form and climbing to 50 and thus hasn't been playing 24/7 for the last three days.
