Get the indicated number of points in battle to unlock the corresponding special unit:

Bothan Spy: 8 points
Clone Commander: 8 points
Dark Trooper: 12 points
Droidika: 12 points
Imperial Officer: 8 points
Jet Trooper: 12 points
Magnagaurd: 8 points
Wookie Warrior: 12 points

Special units are used for special tasks. The Bothan Spy's regeneration ability can be useful for your troops to go in and storm the enemy's defense because they have better stamina. Their stealth ability is useful because it allows you to get into an enemy CP, capture it, and destroy the enemy's vehicles with the time bomb. The Wookies have strength and endurance with their bowcaster, as it will be a one-hit kill for almost any opponent. Their grenade launcher is useful for groups of enemies. The Recon Droid is useful for scouting, backup, and groups of enemies with their self-destruct mechanism. The Dark Trooper is useful for transport and assault. Their Jumppack can carry them great distances across the battlefield and their Arc Caster causes serious damage. Their charge shot should be used on multiple enemies. The Imp Officer is ally support and group assault. Their rage is used for extra damage so that they can storm the enemy's defense. Their mortar launcher is similar to the Wookie's grenade launcher. The Jet Trooper is used for transport and Droideka disabling as well as scrap metal destroying. The Jet Trooper can carry them across them great distances. Their EMP launcher is used for disabling the Droideka's sheilds. Clone Commanders are a brick wall; they have heavy firepower and are useful for ally support. Their chain gun is like a machine gun, with faster firing. Their rally ability should be used to bulk up your and your ally's defense. The Magna-Guard is for heavy fire power and bombardment. The RLR Bulldog is for vehicles and groups of enemies. The mortar launcher is same as the grenade launcher and the recon droid for the above. Droidekas are a brick wall and have heavy firepower. With their personal shield emitter, they are a brick wall. Use the four built in repeating blaster rifles for lots of damage.