Hey there everyone, I am Learn2Eel and this is going to be the first official Tyranid Tactica article! There has been a lot of heated discussion about this codex ever since its release, and while I could cover that here, I'm going to strictly cover the tactics for each unit in the book. Everyone has a different opinion on the Tyranid Codex, and I feel that isn't really relevant to what I want to talk about. However, if you do have any thoughts on the codex and what could have been changed, or what you like, feel free to leave a comment here! Without further ado, I hope you enjoy the article!
The Basics of Synapse
So let's get the facts out of the way immediately.
Synapse - Units with this special rule generate a 12" Synapse bubble. Any unit within that Synapse bubble, including the unit with the Synapse special rule, is Fearless and doesn't test for Instinctive Behaviour.
Instinctive Behaviour - Units with this special rule that are not in Synapse range at the start of each of their turns must take a Leadership test. If they pass, nothing happens. If they fail, they need to roll on the appropriate Instinctive Behaviour table to see the result.
In the 5th Edition codex, Synapse wasn't much of an issue as all of your most valuable units - mostly monstrous creatures - were either Synapse creatures, Fearless or didn't have Instinctive Behaviour. Your cheap, durable Troops choices in the form of Tervigons ensured you had a huge Synapse web, while specialist choices such as Zoanthropes and Trygon Primes provided forward Synapse for more mobile units due to their Deep Strike capabilities. Instinctive Behaviour generally wasn't too punishing, at least in the context of 6th Edition, with units either being forced to move into terrain and act like defensive sentries, or gaining the Rage special rule and thus being more destructive on the charge. It was a big part of the army, but it was more of a bonus than a limitation as you could easily have large Fearless hordes on the cheap.
Enter the new 6th Edition codex, where Synapse provides the same benefits, but Instinctive Behaviour has been redesigned. An extra form - Hunt - has been added, and now units that fail their Instinctive Behaviour tests have to roll on a corresponding chart to see what happens. Units can now fall back, inflict automatic hits on themselves, or be Pinned - and each of these different results comes from a differing table, and will occur in 50% of failed Instinctive Behaviour rolls. It is now also more limiting with all units, not just Lurkers, being forced to target the nearest unit for the most part. Fearless units such as Carnifexes can suffer big-time due to inflicting Strength 9 hits on themselves, a far-cry from them merely gaining +2 attacks on the charge. With Instinctive Behaviour becoming far more of a downside - as it should be, mind - Synapse is now important than ever for Tyranids.
The new codex essentially forces you to stock up on Synapse creatures covering every possible phase of your battle plan; Zoanthropes for baby-sitting the backfield, Tervigons for controlling the midfield, and Flying Hive Tyrants or Trygon Primes hitting the front-lines are the common picks. Your Synapse web needs to survive so that your army doesn't completely break down, and while many Synapse units did get cheaper, many have lost deployment options and potential psychic buffs that gave them increased durability. The answer to this is that you can take more of them for less points, but a balance needs to be struck between taking those supporting-Synapse units that won't do much else aside from be Synaptic lynch-pins, such as Warriors, and your more damaging but Synapse-intensive breakers such as Carnifexes.
This is why I bring a simple rule to every army list with the new Tyranid codex. For each 500 points in my army, I want at least two Synapse creatures. This mitigates the potential for snipers and barrage weapons picking out your Synapse creatures and causing your army to collapse, allowing another Synapse creature to step up and take on the burden of control. Any competitive Tyranid army simply has to have a decent number of Synapse creatures, with me preferring to have at least six Synapse creatures at 1500 to 1850 points limits, the common tournament limits. Where other armies need redundancy in their anti-tank units to handle mechanized army lists, for example, Tyranids need redundancy in their Synapse units so that the army can actually function properly. While this is a limitation unique to Tyranids, there are a lot of upsides; you can field the cheapest Fearless hordes in the game, and much of your army is very cheap for what it does. Just remember that even a mighty Tyrannofex won't be of much use to you if you don't have a Zoanthrope or two guiding it along the path of glory!
The necessity of Synapse units is obvious, but just what units bring Synapse in a Tyranid army list? Let's take a look and work out which ones are the most useful in general by noting the traits key to Synapse;
The Swarmlord - 18" Synapse range, can be boosted through Dominion, foot-slogger.
Hive Tyrants - 12" Synapse range, can be boosted through Dominion and Norn Crown, option to foot-slog or fly.
Tyranid Prime - 12" Synapse range, can be boosted through Norn Crown, foot-slogger.
Tervigon - 12" Synapse range, can be boosted through Dominion and Norn Crown, foot-slogger.
Warriors - 12" Synapse range, foot-slogger.
Tervigon - 12" Synapse range, can be boosted through Dominion and Norn Crown, foot-slogger.
Zoanthropes - 12" Synapse range, can be boosted through Dominion, foot-slogger.
Shrikes - 12" Synapse range, jump infantry.
Trygon Prime - 12" Synapse range, can be boosted through Norn Crown, foot-slogger with access to Deep Strike.
As you can see, Synapse units can be brought in every slot, and each has their own traits. So how does each actually work in practice?
The Swarmlord is the most expensive Synapse option, but can guarantee a 24" Synapse range. Ultimately, as a foot-slogger with durability that really isn't that great for the cost, he's not the best Synapse option.
Hive Tyrants are the cheapest of the monstrous creature Synapse units before upgrades, can easily guarantee a 24" Synapse range through purchase of the Norn Crown and taking the Primaris psychic power Dominion. That you can give them wings and change their unit type to Flying Monstrous Creature means that they only really need Dominion, and this will make them one of your best Synapse units for the cost.
Tyranid Primes have the sole advantage of being true Independent Characters, allowing them to hide in any unit they please - from Termagant hordes to Carnifex broods. They aren't cost effective compared to Hive Tyrants in any sense, including Synapse, but their ability to hide in any unit they please can be very useful in a nine-strong Carnifex list. They have no mobility boosting options, they can't take Dominion as they aren't psykers, and thus can only boost their Synapse range through purchasing the expensive Norn Crown.
Tervigons are the mid-point between a base Hive Tyrant and a Trygon Prime as far the cost of generic Synapse monstrous creatures are concerned. Their additional supporting abilities, namely the unique ability to be scoring, as well as generating extra Troops makes them the best value Troop Synapse unit.
Warriors are over-costed and fragile for the cost, and with no way to boost their Synapse range, their only true use as Synapse platforms is as stock standard broods of three sitting in the backfield.
Zoanthropes are the cheapest Synapse option in the codex, as they can be taken in units of one. Using line-of-sight blocking terrain and their thin - but tall - model means they can easily be hidden near Exocrines, Tyrannofexes with Rupture Cannons, Biovores and other long to medium range units without fear of being targeted. Outside of Hive Tyrants, they are the best Synapse option in the book as they are also Mastery Level 2 psykers.
Shrikes are similar to Warriors in that they are over-costed and too fragile to survive sustained fire power which will invariably target them due to being Synapse units, but they do have the benefit of wings. They can thus keep up with Gargoyles, Raveners and other mobile units lacking Synapse.
Trygon Primes are the most expensive generic Synapse creature, but also the toughest overall and one that can Deep Strike to make up for their 6" move. They are strong generalists with above average shooting and melee capabilities, and are probably your best bet for Synapse outside of Hive Tyrants, Tervigons and Zoanthropes.
My personal recommendation for any army list, regardless of points, is to use Zoanthropes as your primary Synapse units. This is because they are cheap, can be taken in units of one, and are the easiest to hide. From there, Hive Tyrants are the logical sources of Synapse from your HQ slots, with Flying Hive Tyrants in particular being the most effective HQ option in the book. A single Tervigon is a smart option in any Tyranid list simply because of the extra scoring units they provide, as well as their above-average durability compared to most other Synapse units. Trygon Primes may great Synapse units because they can Deep Strike and thus pop up when your army is about to clash with the opponents in their backfield or the midfield, giving you an extra Synapse unit that can't be killed on the first turn.
Keeping Synapse Creatures Alive
Even though I don't recommend using many of these units, I'm going to cover how to keep each individual Synapse unit alive. These units are mandatory to success as Tyranids, so keeping them alive should always be your biggest priority as a Tyranid player.
The Swarmlord - You need Tyrant Guard for the Swarmlord, regardless of how you feel about his five wounds and 4+ invulnerable save in combat. Grav Guns, Heavy Wraith Cannons, Plasma, massed autocannons/missile pods and so on will still kill him with ease. He's expensive, and adding Tyrant Guard jacks his price up even more, but taking at least two is my recommendation in every scenario. The old shenanigans of taking a Tyranid Prime and one Tyrant Guard simply won't work due to the loss of Iron Arm and the massive points increase of the Prime. Make sure the unit moves from cover to cover, ensure they are supported by ranged elements such as Hive Guard and Exocrines so that they don't get baited by Wraithknights and Riptides.
Hive Tyrants (walking) - The generally low cost for the abilities of Hive Tyrants means you might be able to get away with no Tyrant Guard, but I still recommend them anyway. Spending about 100 points to add an extra four Toughness 6 wounds with a 3+ armour save is worth it in any scenario, especially now that the survival of your Synapse units is practically mandatory. As with the Swarmlord, make sure to move from cover to cover as Tyranids lack invulnerable saves against ranged attacks outside of Zoanthropes - a monster without cover and no 2+ armour save or an invulnerable save is just asking to die.
Hive Tyrants (flying) - Flying Hive Tyrants don't need Tyrant Guard - who can't keep up with them - and don't need to rely on rolling up Catalyst despite being "loners". As Flying Monstrous Creatures with Toughness 6, 4 Wounds and a 3+ armour save, they are quite durable and can put out a lot of damage. Keep them supported through mobile ground units such as Gargoyles or other fliers like Crones and Harpies so that they aren't picked off.
Tyranid Primes - These should be kept in the middle of horde units like Termagants and Hormagaunts thirty-strong so that deep-striking and outflanking units can't pop up behind them and force a lot of saves and look out sirs. Another ideal unit to join is a Carnifex brood of two or three, giving the Tyranid Prime eight to twelve Toughness 6, 3+ armoured ablative wounds. While joining Warriors might seem useful due to their stat boost ability, I don't advise it as Warriors are too fragile to make ideal bodyguards for an expensive Tyranid Prime.
Tervigons - As a solo monstrous creature with no access to Tyrant Guard, you need to abuse line-of-sight blocking terrain and cover as much as possible with a Tervigon. Hope to roll up Catalyst, and maybe invest in Regeneration. Make sure to keep up a cover save, even if it means not advancing - a Tervigon can happily sit in the back or midfield if it means it survives and poops out additional scoring units that should only take a turn to grab an objective. Keep your opponent under pressure so that the Tervigon is not their priority; use a mix of flying monstrous creatures and aggressive monsters like Carnifexes or Tyrannofexes to flood the board with viable targets.
Warriors - Given the high cost and low durability per point of Warriors where common Strength 8 weapons are concerned, taking minimal broods of Warriors is ideal as small support units. Take three and hide them in terrain, or move from cover to cover to hide in the midfield. Don't use them aggressively as their damage output is subpar, and making them a target is a mistake.
Zoanthropes - Use units of one or two Zoanthropes to easily hide in cover, much like minimal Warrior broods. The 3+ invulnerable save reduces the value of just sitting in cover without blocking line of sight, so moving up through open terrain isn't a bad idea. Be aware that they are fragile to massed medium or low Strength shooting due to having only two wounds each, so keep them in the middle of your army, rather than at the front. Hiding a Zoanthrope in a building such as a Bastion is a smart, cheap way to boost your Synapse coverage and protect your valuable Synapse unit.
Shrikes - Use the mobility of Shrikes to your advantage, as well as three wounds each. Jump from cover to cover as Dangerous Terrain doesn't really faze three-wound models. Keep Shrike units small so that they are less unwieldy and can be hidden from sight.
Trygon Primes - Always deep strike Trygon Primes - they pay for an ability that is now incredibly rare in a Tyranid list, and can bring out a lot of damage from reserves when upgraded with a Miasma Cannon. If you lose your Synapse early on, having a Trygon Prime deep strike into Synapse range of your forward moving units can be a life-saver.
Thank you for reading this article, and please leave all feedback in the comments section below! I hope this article was useful in helping you to both understand the usage of Synapse creatures, and determine which ones fit your army list better. Thanks again! Eel out.