The Stronghold is a the primary structure of your Base. Its level determines the level to which you may level up all other buildings.
It may be upgraded to a maximum of level 23 and gains additional space in which to build, along with the corresponding possible buildings to fill those spaces, at the following levels:
Stronghold
| Level | New Buildings |
|---|---|
| 3 | Farm, Mine, Food Storage, Forge |
| 5 | Farm, Iron Storage, House, Training Camp |
| 8 | Farm, Mine, Iron Storage, Forge |
| 10 | Unlock Barracks* |
| 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 budilings.*** |
| 23 | Unlocks Alchemy Lab**** |
- Stronghold Level 10: Barracks, Hunter's Lodge, and buildings labeled 'Advanced' are each Advanced Buildings. These buildings 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 SH 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 22: Allows to convert second advanced buildings (except Advanced House).
- Stronghold Level 23: Unlocks Alchemy Lab.
| Level | Iron Cost | Time |
|---|---|---|
| 2 | 4,900 | 1m |
| 3 | 12,300 | 10m |
| 4 | 26,500 | 55m |
| 5 | 47,700 | 2h 15m |
| 6 | 75,600 | 4h 25m |
| 7 | 113,000 | 7h 35m |
| 8 | 162,000 | 11h 45m |
| 9 | 228,000 | 17h 5m |
| 10 | 301,000 | 23h 35m |
| 11 | 388,000 | 1d 7h |
| 12 | 489,000 | 1d 17h |
| 13 | 619,000 | 2d 3h |
| 14 | 753,000 | 2d 15h |
| 15 | 903,000 | 3d 4h |
| 16 | 1,073,000 | 3d 19h |
| 17 | 1,260,000 | 4d 12h |
| 18 | 1,490,000 | 5d 6h |
| 19 | 1,729,000 | 6d 2h |
| 20 | 1,969,000 | 7d |
| 21 | 2,108,000 | 8d 1h |
| 22 | 2,367,000 | 9d 4h |
| 23 | 2,439,000 | 10d 9h |