Bat Cloud is a Fortress upgrade that is available to the Goblin faction. At a cost of 500 resources, this upgrade is one of the cheapest yet beneficial upgrades available to the Goblins. Once obtained a cloud of bats appear above the fortress, giving the fortress an immense range of sight and allowing it to detect any stealthed units within range. This is particularly useful on smaller maps where the vision bonus allows you to see the enemy base and their movements. As most powers require the caster to be able to see in the area the power is being casted, this greatly advances the defensive and offensive capabilities of the Goblins.
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