In Dawn of Titans the Portal is a building that stores Portal Stones, which are used to transport your troops to battle. Upgrading this building increases the number of stones your kingdom can generate.
It takes time for your Portal to produce stones, so being able to store more is very important for prolonged periods of raiding to increase your resources, xp and vp or for capturing enemy land.
You will see from the table of requirements below that you will be limited to 16 Portal Stones until you get to Castle 16.
Raiding an enemy Land only requires 1 stone, but raiding an enemy city requires 3. Capturing enemy Land needs 4 stones, so you will use up your stones relatively quickly if you want to capture Land.
The good news is that your Portal will automatically start generating replacement stones. It takes 4 minutes to generate 1 stone. Upgrading this building does not speed up the process.
The table below has the build cost for each upgrade level, the build time, buildings required and the rewards grated.
Portal Building Requirements
We will update with accurate figures as we can verify them. Please feel free to leave any details you have from Dawn of Titans by commenting below and we will update the data accordingly.