Today we are going to discuss about different ways to deal with the famous "Screamerstar", that we so often see getting fielded nowadays. This usually consists of 1-4 Heralds of Tzeentch with Grimoire(depending on the list and the player's commitment to the unit) attached to 9 Screamers of Tzeentch alongside with Kairos to get the precious reroll on the Grimoire. Νοte that we are not going to debate on different methods to bait,delay or minimize the unit's damage or to disrupt its Grimoire roll by killing the Fateweaver and thus getting an advantage, but rather on direct ways to crack through the unit's tough shell, making it an easy prey for your army.
One of the most obvious ones. While it's not always worth taking the first turn and allowing your opponent to deploy reactively and also to have the last word on the mission, you should really consider it against the Screamerstar. Going first means that you 'll get a whole turn of shooting before he gets his psychic powers off and thus making the Screamers invulnerable. Just make sure that you are going to get clear paths of fire to the unit, because LOS block via terrain is going to ruin your plans.
2) Precision ShotsΝοt so much a rule you can rely on, cause let's face it, there aren't many units out there that can lay down a significant amount of precision shots in order to overcome the look out sir rolls and the Herald's save to eventually kill him, but it is definately a rule you must not forget about when facing the Screamerstar. Special characters, sniper weapons or specific rules that state so, can override the standard wound allocation system and allow you to get your hands on the juicy targets. Specific units who come to mind, that can effectively break through the Screamerstar, are the Tau Sniper Drones(especially with the Ethereal buff) or the Vindicare Assasin(remember this guy?), but I am sure there are more out there.
3) Barrage weapons
An other straight-forward way to manipulate the standard wound allocation system. Just rain down those blasts on the head of the Grimoire Herald hoping he misses his look out sir roll. Often it might be a good idea to focus other elements on the daemon army with this kind of weaponry, but depending on the circumstances, for example if there aren't any other notable threats or if you have a plethora of barrage shots(Thunderfire Cannon or Manticore), going for the Herald might prove itself really rewarding.
Obviously the angle you are going to fire the Screamerstar from plays an important role on which models are going to get hit. In most cases you will see the Screamers to be up in front of the unit in order to soak up wounds, while the Herald who holds the Grimoire will hide in the back in order to survive as long as possible. Naturally, as the game progresses the models are going to get repositioned, with the protection of the Herald being the pivotal aspect of their formation. However, especially after the Screamers will start approaching your units, they will be unable to provide a 360° arc of protection to the Herald. This will leave direct fire paths to the Herald open, that you can exploit by getting in the right position. Fast units or unit that arrive from reserves are especially good at archieving this as they have enough mobillity to flank the enemy's formation.
The most tricky one, but also one you should always pay your attention on. Often the Screamerstar in its attempt to spread out in order for example to avoid blast weapons or to present a bigger threat, finds itself being protected by different values of cover(not that they matter anyway). You can even affect the unit's cover by moving up models of yours in such a way that they intervene between the Screamerstar and your firing units, and thus providing cover to a certain part of the Screamers. The thing is, that by using Focus Fire you can isolate certain models of a unit(depending on the unit's cover saves) and focus them down while ignoring the rest of the unit towards wound allocation. This can sometimes prove itself a really worthy move, especially against units like the Screamerstar, as you will be able (providing that the circumstances allow it) to snipe off the weaker parts of the unit aka the Heralds and thus crippling the whole unit's durability.