All Zerats have the usual knife and pistol along with a combi rifle on most profiles and mines on all but one profile. Multi-terrain also allows them to engage their missions on any battlefield. That is where the similarity between profiles ends. Zerats can choose between a light flamethrower, e/Mitter, Assault Hacking Device and D charges, or replace the combi all together with a Sniper rifle (for additional SWC), or Boarding Shotgun and Grenades on a regular or FO profile. From all this it should be clear that Zerat are mission focused rather than a broad tool box unit.
Zerats have Mimetism, and PH 12 to keep them alive. Without a camouflage state and at BS 11, they are more vulnerable than most infiltrators, and should be deployed with care.
Zerat Boarding Shotgun and Grenades profiles (regular or FO) can start in a great position to throw grenades with speck fire. This can allow them to start attacking midfield enemies from the first order throwing at 9s. Alternately, she can FO first, and then throw grenades indirectly at her targeted foe. The flamethrower can be counter deployed to enemy camouflage, starting right in their face and declaring a discover + shoot. You wont have to declare what weapon you are using until after your opponent chooses to reveal or not, letting you pick your best option. The Flamer can also Intuitive attack against camo tokens in the same fashion. Finally, few opponents expect or plan for a light flame thrower to start over the midway line, making this a good shock piece.
Zerats will die to most concentrated fire. In cover, especially in suppression fire, they can be hard to dislodge, but template weapons, visors, or any decent weight of fire (or long ranged fire) should shift them or kill them outright.
While Shrouded and Malignos fulfill the roll of an infiltrating specialist well, the Zerat offer a cheaper alternative (or, for that matter, you can take all three). Generally they work best when tailored to deal with a specific threat that your list has few options for, or as a cheap gambit piece. In the Morat Aggression forces this is especially useful since they have no other infiltrators and only one AD trooper to start further afield. A special note should also be made for the Assault Hacker with D-Charges, who can do almost every classified objective by herself, if needed.
Since they are more vulnerable than the average skirmisher, the Zerats should be placed with care. Not using your whole infiltration to assure a safer place is a good option. Alternately, you can throw caution to the winds and attempt to deploy over the midline, knowing that at least they can be safe in your own deployment zone if they fail the roll.
Active Turn Role
Zerat want to use their special weapon load out to hunt the enemy troops it was designed to take out. If the mission required interacting with objectives, she will look to do so when it is safe, or at least before the enemy does. The Zerat should retreat to a safe position at the end of their active turn and look to end the turn safely tucked away, or at least on Suppressive fire.
Zerat will often be better off dodging than shooting back. Unless the odds are well in your favor, or the value of dropping a mine or shooting back far outweighs losing the Zerat, just rely on your dodge. An exception should be made for the FO who will often Flash Pulse better than she dodges.