NOTE: Portals are being phased out with the advent of faster Primarch Travel. Existing Portals will still exist, but if a castle is conquered or if upkeep is unpaid, the Portal will vanish forever.
These allow you to quickly move your Primarchs between different castles your team owns, especially if they’re far away from each other. To make one of these portals, your castle needs to have the ‘Tower’ infrastructure building built. Then, construct the portal. You can then send Primarchs with troops through, up to a daily capped number of troops. This cap is based on the Tower’s level, so the higher level your tower, the more troops you can move around each day. Like all other infrastructure, the portal is not functional if you have enemies on the castle, or if upkeep is unpaid.