A defender (also known, often perjoratively, as a fender or fenda) is a nation or organization which attempts to counter attacks on regions and the invasion of regions.
Often, defenders use a WA puppet endorse the native WA Delegate, although when the native delegate is inactive, defenders usually endorse a defender delegate who takes the delegate position, ejects the invaders, and leaves.
Defenders are usually parts of defender organizations, or groups of defenders. The biggest of these organizations was the Alliance Defense Network or ADN. The largest current one is The United Defenders League.