"Trains elven Defenders to block and fight incoming enemies."
The tower trains three elven soldiers, called defenders. Defenders are the most basic soldier, with low health, negligible damage and little armor. They are able to hold and fight enemies, but should not be relied upon to actually bring them down, as most enemies will be able to kill them.
Despite possessing armor, the Defenders are still highly vulnerable to damage and can die in seconds. Their lack of a ranged attack also makes them less versatile compared to other Barracks. It is advised to upgrade them to Warden Barracks or higher as soon as possible, if not immediately after they are recruited.
The quote "By the light of the moon!" is also used by the Sylvan Elves in the original Kingdom Rush. This may mean that there's a direct connection between the elves of the Elven Continent and the sylvan elves.
When upgraded to the Bladesinger Hall, the names of the elves carry over.
Defenders actually deal more damage than Militia, with a damage of 1-4 as opposed to 1-3. Overall, defenders are actually stronger than militia but take 4 seconds longer to respawn. Moreover, the Defender Barracks itself is significantly more expensive than the Militia Barracks.