Clans are groups inside the game. Clan tags are usually used in tournaments to identify players.
Try learning Callouts to inprove your game: https://wiki.unvanquished.net/wiki/Call_Outs
To add your clan tag go to menu>player and click on "nickname" then put
^1[Clan-Tag](another colour)your name
Current in-game clans:
The first and only clan as of now is:
King was founded by Derek and has two members:
///Put other clans here and their description and list players