The Harridan are described as the Aliens Engineers and Scouts, equipped with Jetpacks and long range weapons, making the Harridan a formidable foe to encounter, as well as a versatile one that can get to a good position to attack human targets. Incapable of higher brain function and slaved to their suits from creation, they are more of a creature to pity, it nonetheless must be respected.
Harridans are found in mid-late game and are often found with Androns and Ceasans. The earliest you can find them is on Landing Ships.
The Harridan's are capable of using Jetpacks to allow them to gain a height advantage. Harridans are usually found using the high ground to their advantage. Coupled with their high reflex chance and high natural accuracy, this means anyone walking near a Harridan will usually draw deadly sniper fire from them. In addition to their exclusive usage of Alien Sniper Rifles and Alien Plasma Cannons this makes the Harridans a deadly foe. Great care should be taken when approaching a known Harridan.
However the Harridans usage of high ground usually means they lack any actual cover. Meaning they can be easily cut down. Their advantage is using their main race, usually Androns, as a buffer.