The Stronghold is the primary structure of your Base. Its level determines the level to which you may level up all other buildings, i. e. no other building may have higher level than the Stronghold. (The dependence works in the other direction as well - the higher-level upgrades require having so much Iron at hand that they can't be started before leveling Iron Storages near their maximum currently allowed capacity.)
Te Stronghold may be upgraded to a maximum of level 25 and gains additional space in which to build, along with the corresponding possible buildings to fill those spaces, or other Base developments, at the following levels:
|3||Farm, Mine, Food Storage, Forge|
|5||Farm, Iron Storage, House, Training Camp|
|8||Farm, Mine, Iron Storage, Forge|
|11||Farm, Food Storage, House, Training Camp|
|15||Farm, Mine, Iron Storage, Forge|
|20||Farm, Food Storage, House, Training Camp|
|21||Unlock Hunter's Lodge and Advanced Buildings**|
|22||Allows to convert second advanced Farm, Mine, Food Storage, and Iron Storage|
|23||Unlocks Alchemy Lab***|
|24||Allows to convert third advanced Farm, Food Storage, and Iron Storage.|
|25||Unlocks Hero Academy****|
- Stronghold Level 10: Barracks, Hunter's Lodge as well as buildings labeled 'Advanced' convert already-leveled buildings into the Advanced one. See each individual page for more information on its own requirements for conversion. Because of said conversion, no new building slots are acquired at Stronghold level 10 or 21.
- Stronghold Level 21: Unlocks the following Advanced Buildings: Advanced Farm, Advanced Mine, Advanced Food Storage, Advanced Iron Storage, Advanced House and Hunter's Lodge, which can be further upgraded to level 10.
- Stronghold Level 23: Unlocks Alchemy Lab.
- Stronghold Level 25: Unlocks Hero Academy.
|Level||Iron Cost||Time||Iron/hr||Iron Storage prerequisites|
|2||4,900||1m||294,000||(to be added)|