Hosa,
When you register and do not join an existing clan, you must make a name up for a in which you are the Daimyo. There are many one-person clans because of this, but you can play still play as a ronin. The clan thing is for multiplayer clan ladder stats only. If you decide to join a clan later you can re-register and list the clan's name that you are joining. I hope this helps some, Elmarko of Fearful Ways