Cities

City is a special terrain which can generate gold and train unit as long as there is enough population. You can gain cities by capturing villages or enemies' cities. They are really important and should be protected at all cost.

Your first city passively has +1 gold generation and +1 sight

Leveling up cities
Each city has 8 surronding tiles of territory. Performing certain actions in a city's territory gives it development points. These actions include:
 * Collecting resources
 * Building facilities
 * Upgrading facilities
 * Making connections with the capital

Cities level
Leveling up cities requires a certain amount of development points. The amount required increase after each level. After leveling up, a city gain a bonus depending on the player's choice:
 * Lv.2: (2 D-points) +5 golds or +1 sight
 * Lv.3: (3 D-points) +1 territory or +2 population
 * Lv.4: (4 D-points) +3 D-points or +1 gold generation
 * Lv.5: (5 D-points) One of the 2 guardians

Capitals
Capital is a special kind of city which passively has +1 population. Additionally, they can gain huge development points by connecting to other cities.

Each tribe starts with 1 capital and a new one will be appointed if current capital is captured. Captured capitals will lose the capital title and become a normal city, thus losing 1 population.

Unit training and guardian summoning
Newly summoned units act can't attack or move for 1 turn but still can counterattack and occupy the city. Occupied city, either by your opponent or yourself, can't train units or produce gold

Upon reaching level 5 and above, Cities will instantly summon a guardian. If the city is occupied, either by your opponent or yourself, the occupying unit will be forced to move one tile in a random (?) direction and the guardian will be summoned

Summoning guardian is an excellent way to force enemy's force away from your city (especially Stone Golem as they are very defensive)