Secret Knowledge categories

In contrast to main Knowledge, secret Knowledge is not available immediately — each stage unlocks once the Oracle building reaches a certain level.

First stage

Secret Knowledge of the first stage becomes available to be learned after you reach Oracle level 31. It is divided into three categories:

• Attacking — substantially improves your troops' stats during attacks.
  
• Defending — substantially improves your troops' stats during defense.
• Fortresses I — substantially improves your troops' stats during battles for Fortresses.

Second stage

Once your Oracle reaches level 36, you will be able to learn secret Knowledge of the second stage. It is divided into six categories:

• Offense — substantially improves the offense of your troops.
• Defense — substantially improves the defense of your troops.
• Health — substantially improves the health of your troops.
• Tier VIII Troops — improves the offense, defense, and health of your tier VIII warriors, reduces their training cost, and increases the speed at which they can be trained.
• Towns — significantly improves your troops' stats during battles for Towns.
• Fortresses II — substantially improves your troops' stats during battles for Fortresses.