Well, Rider Camp is a troop building in the game You can say that this is like a barrack where you can Train your Riders. So You have to Upgrade this building to level 11 and after that, you will be able to Upgrade your Watchtower to Level 12.
You have to Upgrade Rider Camp to unlock more advanced units. Below you will find Rider Camp Upgrade Requirements and Cost
Rider Camp Upgrade Requirements
| Level | Requirements | Iron | Wood | Energy | Upgrade Time |
| 1 | N/A | N/A | 80 | N/A | 0 Sec |
| 2 | N/A | N/A | 240 | N/A | 10 Sec |
| 3 | N/A | N/A | 1.2K | N/A | 48 Sec |
| 4 | N/A | 2.4K | 2.4K | N/A | 2:23 min |
| 5 | Watchtower Level 5 | 9.6K | 9.6K | 9.6K | 4:06 Min |
| 6 | Watchtower Level 6 | 19K | 19K | 19K | 09:25 Min |
| 7 | Watchtower Level 7 | 58K | 58K | 58K | 18:50 Min |
| 8 | Watchtower Level 8 | 92K | 92K | 92K | 28:15 Min |
| 9 | Watchtower Level 9 | 220K | 220K | 220K | 1:02:48 Min |
| 10 | Watchtower Level 10 | 330K | 330K | 330K | 1:21:38 Min |
| 11 | Watchtower Level 11 | 830K | 830K | 830K | 1:42:03 Min |
| 12 | Watchtower Level 12 | 1.4M | 1.4M | 1.4M | 2:02:27 |