<The Flagon> makes its home on Kronos I. It's a solid group of players who hold RP gatherings and are preparing for PvE content.
As far as Kronos II is concerned...
<Arcane Light> is the only established RP guild I've crossed thus far. Their leader, Sallie, is friendly and approachable. I'm to understand they run regular events.
<The Order> is a much smaller group of players arriving from Nostalrius with RP PvP in mind when the time comes.