Gateway

Gateways are a low cost support structure, at 10 thorium per gateway. Unlike every other structure in the game, gateways are the only ones that can be passed through by units. Gateways are used to allow your units to pass, while making enemy units go around them. They can be used to allow allied units pass enemy towers, while making enemy units pass through your towers.

Gateways can also make your thieves less useful, if the thieves do not meet up with enemy forces.