Economic research includes Building Construction research to increase your building speed as well as research like Farming Mastery and Logging Mastery, which increases production of resources (e.g. Grain, Wood etc.).
Within these categories, you can also carry out research to increase Army Capacity and gathering speed for Diamonds and resources.
City Defense Basics
City Defense research includes Wall Reinforcement and unlocking Fortifications. You can use this research to improve your City Defense Power and unlock advanced Fortifications to resist invaders!
Military research includes Training Speed bonuses, Spying that provides more information on the enemy, Marching Speed bonuses, unlocking troop types at each tier and bonuses to troop attributes (Attack, Defense, Health etc.).
This category of research clears away obstacles on your path to power by unlocking troop types of higher ranks and increasing attribute bonuses for your troops.
Expedition & Pacification
The Expedition & Pacification category consists of Pacification Strategies research that unlocks higher level Rebel Leaders, research surrounding Motivation such as raised Motivation cap, increased Motivation recovery speed and reduced Motivation spent, and research that grants bonuses while slaying Rebel Leaders including increased expedition combo cap, march speed, damage etc. This category of research allows you to unlock and slay higher level Rebel Leaders and increases attribute bonuses for expeditions.
City Defense Specialization
By completing research in the City Defense Specialization category, you can gain bonuses to City Wall attributes, Fortifications attributes, City Wall reconstruction speed and Fortifications construction speed. You can also unlock Fortifications Restoration, which enables you to restore damaged Fortifications. This saves both time and effort.
By completing research in the Military Specialization category, you can unlock features such as Coordinated Gathering and Troop Formation, which enables you to set the number of troops you want to deploy with a single tap. Here you can also increase the Hospital's Healing Speed, troop Training Speed, Marching Speed and number of soldiers trained at the barracks, raise the cap on Talent Archive configurations, equipment archive configurations and pre-edited army combinations and reduce training costs for soldiers at all tiers.
By completing research in the Marching Formations category, you can unlock various types of formations, increase attributes related to gathering, increase Barracks and Hospital capacity and increase Gold Dragon production and capacity. You can also weaken defending armies' Attack, Health and Defense.
By completing research in the Commandership category, you can increase resources received from Rescue and resource storage capacity, increase your Stamina limit and army shelter capacity, boost attributes related to attacking Rebel Camps etc.