Here’s our forum thread which explains the specifics of the guild:
As for your question, we do have a Horde-side guild, but it’s primarily just for alts of people that are already part of the guild on Alliance. This is because the use of Horde characters is still pretty inconvenient when it comes to events, and the lack of unified guild/raid chat doesn’t really make things much easier.
That said, at least a few people in the guild have Horde side alts around now and then.