Oil pots tip over and set ablaze a large area when enemy troops get too close. Oil pots may be placed on any stone wall or tower within the boundaries of your castle, and require pitch to place however, they do not require building, so may be placed with immediate effect. To build smelters in a capital's castle, a Sergeant-at-Arms Office must be placed and upgraded.

To build smelters in a village castle, Defences Level 5 must be researched. Each smelter will provide enough oil for five (5) oil pots. To place boiling oil pots around your castle, you will first need to place a Smelter, which requires Iron to build. Killing pits are one (1) tile each in size. To build killing pits in a capital's castle, a Sergeant-at-Arms Office must be placed and upgraded. To build killing pits in a village castle, Defences Level 2 must be researched. The base cost of a single Killing Pit tile is 100 iron. Killing pits may be placed anywhere within the white line (build zone) for your castle, and require iron from the stockpile to build. Killing Pits are deadly pits containing iron spikes, and are placed in the grounds of the castle in order to injure any attacking troops which walk over them. To build a guard house in a capital's castle, a Sergeant-at-Arms Office office must be placed and upgraded. To build a guard house in a village castle, Defences Level 1 must be researched additional research gives access to stronger guard houses. The base cost of a Guard House is 400 wood. Guard houses require wood from the stockpile to build.

Each guard house allows an additional 10 troops to be placed within the castle, and a maximum of 38 may be placed. Guard houses are used to increase the number of defensive troops within a castle without any guard houses, the castle's capacity is 20 troops.

Stronghold kingdoms research guide