A spy is the only follower who can disguise himself into the color of an enemy tribe currently inhabiting the planet. The best way to see these Followers is after the Level An Easy Target when the Spy Training Hut is invented by the Chumara Tribe, the player's next door neighbors in this Single Player level.
The foreground of the attached picture shows the Blue Tribes Spy Training Hut, 4 Followers, of the Spy Grade. They are distinguished to the player as Followers in black jackets, pants and the accompanying color. To the enemy, they are seen as Braves. There main claim to fame is the ability for them to disguise as an enemy follower, sneak into an enemies base and light Huts or trees on fire.To disguise simply select one Spy, or multiple spies, and click an enemy Tribes color on the left panel to the right of the shaman shortcut icon. The icon switches to a masking button and with one simple left click the spy's middle color slowly changes to the selected enemy Tribes color. Spies can only be commanded to sabotage (ignite) trees and enemy structures. For undamaged buildings, the procedure to do this is the same as attacking; simply select the spy and left-click to set it ablaze. If a spy is not disguised when attempting to set a fire, he will be quickly attacked.
The spy's strength is the lowest of all units, 1 Brave can easily kill a Spy, bare handed in less than 6 seconds whilst leaving the Brave just at ¾ health. It approximately takes 3 spies to kill just one Brave.
An enemy Spy lurking in ones base can be uncovered by simply finding one and right clicking them. Another tactic is to set a Spy in a Tower and let him uncover spies attempting to gain entrance to ones base.
Putting a Spy in a Tower will unmask all enemy spies in a large area. Spies have the largest viewing range in a tower of all followers, making them excellent lookouts. Also, all the area under the spy's tower range will be cloaked from world view the same as Fog of War, hiding details about and building or followers in the area.
A good tactic to use with spies is to attack the training huts (warrior, fire warrior, preacher and spy) or the vehicle huts (boats and balloons) as this will temporarily prevent the enemy from producing any skilled followers or vehicles. Another good tactic is to burn down the enemies defenses so your shaman can walk in safely.
Simply select a group of six spies and assign three too attack one side of an entrance, and another three to another side of an entrance, or divide up them by two, and make 2-2-2 to attack an enemy's base. Simply bookmark each new unit and start assigning each to set ablaze Huts Burn multiple Huts (Ctrl and left click three Huts) for the 1st group, five Huts for the 2nd and three Huts for the 3rd group, then further this by assigning each ones to attack separate Huts.
Spies can burn multiple Huts by holding ctrl then clicking each Hut.