Clan

Clans are associations of players in the game of Tabula Rasa. There are two types of clans, PVP and PVE.
PVP clans are able to participate in wargame feuds, which are a sort of contained warfare agreement where both clans "at war" agree to a set of terms, including the amount of time where the two parties will remain at war. This affects the whole clan, compared to the more "individual" nature of wargame duels.
Most clans are a social hub for players for teaming, companionship, etc. Many have forums and teamspeak/ventrillo servers on top of the teamchat feature already present in the game.
Rank within the clan progressively gives more abilities, such as the ability to send clan invites to other players.