Defense is quite a bit different from attack because defenders from different villages, and even different tribes, can band together as one.
When a village is attacked, all the troops currently in the village will act as defenders (excluding troops caught in trappers of course), automatically fighting off the attackers, regardless of who owns the troops.
When defending a village, there are also several important buildings involved:
- The city wall (or palisade, or earth wall) is the most obvious. This grants a percent bonus to the cumulative defense values of the troops.
- The residence or palace provides a fixed bonus to the defense values as well.
- The rally point allows you to see incoming attacks, so that a proper response may be prepared in advance.
- The stonemason defends buildings against catapult attacks, but may only be built in a capital.
- The town hall allows great celebrations, which help reduce the loyalty penalty of enemy chiefs, should your troops prove insufficient.
- The trapper used by the Gauls can also be used to capture attacking troops and reduce the strength of their force.
- The armoury can also be used to improve the defensive strength of all troops built within the village where the Armoury resides.
- A cranny protects resources from raids and attacks.
- Finally, the granary stores crop for the defending troops to eat. Troops who starve to death don't help you!
Infantry defense and cavalry defense[]
Defensive values are divided into two categories: infantry defense, and cavalry defense. Some units are adept at only one of these categories, while others are good at both. If the make-up of an incoming attack is known to be largely cavalry, then units such as the Spearman, Phalanx, Legionnaire and Haeduan are the best choices for defense against it. If the attack is largely infantry (and siege weapons count as infantry), then units such as the Praetorian, Druidrider and Paladin are top picks.
When in doubt, infantry defense is usually considered more important than cavalry defense, because infantry is faster to produce, cheaper to maintain, and generally more numerous throughout the game. But it's good to have both types of defense covered, just in case!
You may want to keep a number of scouts in each of your villages, to prevent scouting. This often deters the enemy, or causes them to guess at what you have. If they misjudge, they may lose all their troops as a result!