Amos Twinly the Scribe is an NPC at the Clan Camp.
You have to talk to him to start your clan. He will then give you a scroll which you need to use on other people to invite them to your clan. You need to have at least four other people to start your clan by going back to him and telling him you have a full list. You can then enter your clan name, and your clan is created.

The Scribe's flag.
After you start your clan the scribe gives out vexilla to clan members for them to plant in the ground to show off the clan they are in.
If you ask the Captain of the Guard about clans, he will send you to the Scribe. The Scribe gives you all the information you need about clans. Except information about Rated Clan Wars, the Sergeant-at-Arms will help you with that.
As of 16 May 2011, clan owners can speak to the scribe to change the name of their clan. They can only do this once every 28 days, however.

The Scribe's camp.
Website features | Clan Hiscores • Clan Home • Clan Forums |
In-game features | Clan Chat • Clan Settings • Clan cloak • Clan vexillum • Clan jobs • Clan Citadels • Clan Admin Messages |
Clan Camp | Captain of the Guard • Clan charter • Clan meeting tent • Scribe • Sergeant-at-Arms • Clan noticeboard |
Rated Clan Wars | Rcw badge • Rcw rules |