The Observer is the Protoss spy, designed to detect while being undetected. For this reason it has no means to attack or defend itself; its only protection is its Protoss shield. Permanently invisible, the Observer can infiltrate enemy settlements and spy on them. Its use as a scout is extremely profitable too as it has a very long sight, and positioned at key locations can warn of any impending assaults and thus destroy the element of surprise for the enemy. Better even, when Protoss are attacking they can have a couple of Observers accompanying their armies, making the enemy’s cloaked units useless until they have found where the Observers are and dispatch of them, which isn’t an easy task. The only thing to remember when using Observers is to stay clear of enemy detectors.