Amtgard
Amtgard is a fast paced medieval combat game, with many similarities in common with Dargarth. They use an armor system with variable values (heavier armor is generally worth more), have classes and magic, and hold adventures/quests that utilize monster NPCs.
There are some major differences between the two organizations, however. Amtgard is a massive national organization, broken up into semi-independent "kingdoms," which are broken up into local chapters (which have varying names, based on size). They also do not utilize a "territory map," except for occasionally on a individual group level.
On a game-play level, Amtgard does not require sufficient force for hits to count. Additionally they do not allow grappling or shield bashing, and significantly limit offensive shield contact. They are known for having very high level top tier fighters and excellent finesse and footwork (which will obviously depend on location and individual fighter).
The local group(s) are a part of the Kingdom of the Northern Lights, which is composed primarily of the Puget Sound region Amtgard chapters.
In Dargarth, Alliance Company was the "Amtgard country," until it's dissolution, and was named after a local fighting company based out of Inland Ocean (Redmond Amtgard).