"Defense or Offense? Why not combine the two? This defense building allows you to disguise your protective Mercs, who will be unleashed to respond mercilessly to any attack."
This defensive building is different from the towers. You have to put mercenaries in this building and these mercenaries will come out and fight when you are being attacked. You can only put ground mercenaries in the Watch Post, it is not possible to add Hezarfen or Gentle Healer to the Watch post. At the moment it is not possible to use the Watch Post against attacking flying mercenaries and beast. If the Watch Post is empty nothing will happen when you get attacked. The most used mercenaries in the Watch Post are Khamikazee and Bedouin Brute.
Extra Watch Posts
To build your 2nd Watch Post you need City Center level 5 To build your 3th Watch Post you need City Center level 7 To build your 4th Watch Post you need City Center level 8