Genestealer Cults Summary Page

This page serves as a summary for all the Genestealer Cults codex reviews that have been posted on to Warpstone Flux. The ordering follows the presentation within the codex, followed by the formations and the Insurrection detachment. 

HQ
Patriarch
Magus
Primus
Acolyte Iconward

Troops
Acolyte Hybrids
Neophyte Hybrids

Elites
Hybrid Metamorphs
Purestrain Genestealers
Aberrants

Fast Attack
Chimera
Armoured Sentinels
Scout Sentinels
Goliath Truck

Heavy Support
Goliath Rockgrinders
Leman Russ Squadron

Formations.
All Formations and Cult Insurrection Detachment.

Genestealer Cults Review: Formations

The formations in the Genestealer Cults codex provide the army with some very entertaining options for possible builds and come with some neat bonuses when employed.

Cult Insurrection Detachment.

For the price of a few formations, the entire army gets some very nice bonuses in this detachment. Patriarchs re-rolling traits if the warlord (and why wouldn't they be?); everything infiltrating (except vehicles); shrouded for those that already have infiltrate on turn one; manipulating reserve rolls by 1 in your favour and against the enemy; and regaining dead members that are in on-going reserves. This latter facet can be really powerful as it represents an easy way to get back a special weapon where needed, or even an icon. Overall, it is very powerful and can really be powerful when played right (particularly return to the shadows). Just be careful not to get wiped off the board whilst many are situated in reserves though -- that could really make a good game turn sour quickly. 

Command Formations.

Lords of the Cult doesn't do anything other than provide models. Meh.

The First Curse necessitates a large unit of genestealers, but they all get a bonus of some kind. Some are nice, others are situational or okay. 

Brood Coven is okay and provides a number of vital special rules bonuses. This can be good for building a very powerful segment of the army that has an excellent attack possibility and even could approach a death star level of power. Almost.

Core Formations. 

Brood Cycle is a very large formation requiring a significant investment of cash to purchase the models involved. Having said that, it is nice as it provides bonuses to WS and Ld and a bubble of furious charge. It'll eat up some points, but resonates very well with the reserves back and forth that you will undertake with this army.

The Neophyte Cavalcade plays to a more mechanised army overall. It provides a way to grant outflank to vehicles and a 50-50 chance to ignore crew shaken and stunned. 

Auxiliary Formations. 

The Doting Throng provides a nice bubble of zealotry and re-rolls to psychic tests for a Magus with this. 

Subterranean Uprising is a nice way to grant infiltrate (and this in turn resonates with the Cult Insurrection rules, of course). The bonus for having the Primus is nice and not to be overlooked either. 

Demolition Claw is another one that would be good for a mechanised approach. I personally don't like all the dynamite knocking around due to the short range myself, but I can see its appeal. 

Deliverance Broodsurge is a good resonance with the Neophyte Cavalcade and provides good bonuses for taking lots of Goliaths. Really for the mechanised orientated force, but could work in other places as well (particularly high points value games). I would be tempted to stick to all infantry armies for the Insurrection though.

The other formations provide no particular bonuses, but are a nice way to gain purestrains (Shadow Skulkers), aberrants or metamorphs (Cult Mutants), and sentinels or leman russes (Brood Brothers). They're a nice way of tailoring the army list for particular themes.

My own take would be to go down a themed route: (1) all infantry and focus on the hybrids and everyone else; (2) mechanised - go all out with vehicles wherever possible; (3) pseudo-Imperial Guard and even take allies from said codex; (4) monsters and take allies from the Tyranids codex to represent something later in the invasion of a planet. All of these options (and more) are viable and can be represented through the Insurrection detachment readily. 

Genestealer Cults Review: Leman Russ Squadron

Background.
Stolen directly from the Imperial Guard of the `host' planet, the Leman Russ battle tank is well-known for what it does on the battlefield across the Warhammer 40,000 Universe.

Strengths.
This is a great tank! Excellent front armour, great side armour and versatile set ups. I don't really dislike much about them overall. I guess it ultimately depends on the kinds of opponent that one expects to face. Having said, that, some of the pie plates do rely on BS=3, so that's not so awesome. A large number of shots would be better to ensure a few hits arguably. But I still like and respect the Leman Russ.

Weaknesses.
The rear armour is only 10. But you all knew that, right?

Builds.
There are a lot of builds to consider here. What is below is just a sub-sample of the ones that appeal to me personally.

Leman Russ, Eradicator, heavy flamer (120 points).
This basic battle tank is really versatile. I like the flamers for defence and assault roles. The eradicator nova is a mid-range beast that can bring the hurt in numbers to Imperial Guard, Eldar, and the like.

Leman Russ, Exterminator, heavy bolter sponsons (140 points).
A lot of dakka here to get around the BS=3 issue. Not much not to like really!

Leman Russ, Vanquisher, Multi-melta sponsons (155 points).
Heavy, high strength shots at long range is still awesome no matter what enemy one is facing. However, the BS=3 is a really big issue here though. That said, certain builds of the cult armies could outflank this beast, so the above build is equipped with multi meltas to help take advantage of this. Add an extra lascannon if the points allow.

Leman Russ, Battle Cannon (150 points).
Large blasts and large ranges. Very nice. Add plasma cannon sponsons if desired? A hunter killer missile as well? Perhaps a lascannon too?

Genestealer Cults Review: Goliath Rockgrinders

Background.
As the name suggests, the rock grinder grinds rocks. This is made evident by the grindy rock drill dozer on the front designed for the grinding of rocks.

Its chassis is in common with the Goliath Truck and is a bit of an upgrade from said truck. Like most things in the Cults armoury, it has been stolen, adapted and put to use of the day of light when the cult springs forth from the darkened mines that they have long been labouring in.

Strengths.
Most obviously, the Rockgrinder has a better armour rating than the goliath truck and is not open topped. Arguably it will be hanging around longer. And (rules as written), it can transport purestrain genestealers.

The rugged construction is a nice boon in common with the truck that provides a "save" of sorts against crew shaken, stunned and vehicle immobilised results.

Weaknesses.
Unlike the truck, this is not an open topped vehicle. Whilst this is a strength in terms of not dying quicker, clearly it also means that any transported cultists cannot assault out of it so readily.

The weapons are not much to write about here. Although the strength is good, the BS is really what makes this less than tempting overall. I can see a good use for the clearance incinerator option though. The torrent is very nice and the flamer template bypasses the poor BS of the vehicle.

Builds.
Not many options here, but here are two.

Rockgrinder with a cache of demolition charges (80 points).
Yeah, they're okay. Nothing special though. And one could subtract off the charges to save on valuable points to be honest.

Rockgrinder with clearance incinerator (80 points).
I like these ones due to the torrent. Several of these can be very nice in a squadron. 

Genestealer Cults Review: Goliath Truck

Background.
Along with others, I was disappointed to not see cult limo's in this army list. The Goliath makes up for this a bit by being fluffy in terms of an army based around hard working hybrids hidden from society for a long time down in the mines (or elsewhere).

Strengths.
The Goliath is open topped which means that anyone embarked on it can assault directly from it. This is fabulous and resonates very well with the melee aspects of the army.

However, costing more than a rhino and being open topped means it won't last as long in all probability.

The weapons are nice enough with a twin linked auto cannon on board that will make a difference to the truck. The heavy stubber is neither here nor there, but its okay.

On top of this, the rugged construction rule is great for keeping the truck going come what may.

Weaknesses.
Purestrains cannot get on board. Presumably their claws are a bit too sharp?

Builds.
The only real question here is whether to take demolition charges? The range of these is very low and hence there's a good chance of blowing up the truck through their use. But if you have the full hull points intact, then it might be worth it as a one off to take out some terminators before charging in to mop up the rest with some rending weapons. Hence, I would recommend:

Goliath (50 points).
The basic build is actually really nice overall!

Genestealer Cults Review: Scout Sentinels

Background.
Like other equipment in the Cults, these scout sentinels probably once belonged elsewhere and were stolen by infiltrators in the cults or put aside for the right moment.

Strengths.
They are a very cheap way to get some heavier weapons in to an army.

Secondly, they can place themselves in to a great position with scouting and move through cover to provide a bit of an alpha strike tactic.

Weaknesses.
They are very vulnerable with a weak front armour, two hull points, and being open topped. In other words, they are going to die very quickly if anything is pointed at them.

Builds.
Don't spend too many points here, but do take them in multiples so as to make your opponent work for that first blood victory point.

3 Scout Sentinels with missile launchers (120 points).
Flexible in terms of having blasts or high strength shots, but otherwise not likely to shine too much without back up. Swap for auto cannons as desired.

3 Scout Sentinels with heavy flamers (105 points).
Great for crowd control against Imperial Guard and the like. Fun when popping up on the field unexpectedly. 

Genestealer Cults Review: Armoured Sentinels

Background.
Much like other equipment in the Genestealer Cult arsenal, the sentinels were more than likely stolen and set aside for when the time was right. Or downright just taken on the right day by hybrids that had infiltrated the local Imperial Guard. They are well known to Guard players and have very similar uses here in the Cults army list.

Strengths. 
Their front armour is superior to the scout sentinel and this will provide some additional protection where required. The ability to take weapons like plasma cannons is very nice and one that should be exploited.

With certain formations, they can also outflank which is hideous. Overall, they are a very cheap way to get some heavy weapons in to play.

Weaknesses.
Look. Let's be blunt. They're going to die. Quickly. Hence if you don't want to give away free victory points for first blood then I'd recommend taking more than one in a squad. The BS of 3 is distinctly average as well. The blast weapons (plasma cannon especially) offsets this a bit. Hence the choice of weapon is rather critical here.

Builds.
A few thoughts.

3 Sentinels with plasma cannons (150 points).
Compare this price to something like a space marine dreadnought and you can see why I like this. Sure, it doesn't hit hard in melee, but its not built for that. The triple plasma blast is hideous to most opponents. Three of these squads is deadly. Try outflanking one for laughs. They can be deadly in all truth!

3 Sentinels with heavy flamers (120 points).
Certainly meant to outflank and take out troops inside bunkers.

3 Sentinels with auto cannons (135 points).
The attraction here for me is the double tap on the auto cannons. Sure, half will miss, but the 3 shots that hit on average are still S=7. This can be very nice and add weight where its needed. I still prefer the plasma though.

3 Sentinels with missile launchers (150 points).
Coming with blast templates like the plasma cannons and able to threaten others with krak, they are flexible, but not shiningly brilliant. 

Genestealer Cults Review: Chimera

Background.
Stolen, hidden and ready for use when the cult spews forth from its hidden tunnels, the Chimera is a mainstay of the Imperial Guard and its uses are probably well known.

Strengths. 
The Chimera is arguably one of the nicer transports in the game since it is able to pump out plenty of shots from the las gun arrays, the heavy bolter and the multi-laser.

Water is also not an issue for its movement -- the Chimera is amphibious for those of you who might be like me and regularly overlook this fact.

Weaknesses.
Yes, it costs more than a space marine rhino. But so what. Its a bit better really. The only negative is shared with the rhino -- this is not an assault vehicle.

All that said, there are few other forces in the game that can make all their transports infiltrate and (or) outflank. This is terrific and could readily be built upon with some choice upgrades.

Builds.
There are not too many builds to consider in the absence of formations. Here are a few.

Chimera (65 points).
The naked build with standard equipment remains a mainstay of any Imperial Guard type army. It is excellent here as well.

Chimera with heavy flamers in place of both multi laser and heavy bolter (65 points).
Very nice for outflanking some opponents when required. Take a dozer blade or hunter-killer missile to taste.

Genestealer Cults Review: Aberrants

Background.
Their origins are not exactly pinned down well, but the Aberrants come along in almost any hybrid generation. Perhaps they're just mutants or bad reactions with the host genes. Or maybe they're thanks to tinkering of the other hybrids in gene slicing. Whatever the origin, they are strong and hard hitting.

Strengths. 
I like their stat line with a good Strength, Toughness and 2 Wounds each. Very nice indeed.

However, they might need to have some back up from the psychic might of the Patriarch or the Magus in all reality. Add in some furious charge and other biomancy and you're looking at a very hard hitting unit indeed.

Weaknesses.
Like most of the rest of the army, the 5+ save is not going to do them very well against bolt guns sadly. Their initiative is not high, but it probably does not need to be.

The major gripe I have is their points cost. By this, I mean terminators are better value for points just about. Hence, I don't think that the Aberrants are a competitive selection overall. But they do have their uses (vehicle killing).

Builds.
Not many options here: only additional squad members and the choice to take hammers over picks. I like the hammers for the AP and the S bonuses myself -- the higher the S, the better they can take out tanks, after all.

8 Aberrants all with hammers (240 points).
Unsubtle and a bit of a hammer unit, pun not entirely intended. Use them to take out tanks.

Genestealer Cults Review: Purestrain Genestealers

Background.
Siblings to the Partirach, the purestrains are what genestealers should be and have been all the way back in the early days. Fast. Deadly. And alien.

Strengths.
These alien xenos are not the same as the ones on board the hive fleets. They're strictly better thanks to a 5+ invulnerable save from their Hyper Reflexes rule. This is just what the doctor ordered frankly!

Although they have no ranged weapons, they get infiltrate, fleet, move through cover, stealth rending, and the other usual cult rules. And if joined with a Patriarch, they get furious charge as well. Very nice indeed and certainly worth doing if you're not getting furious charge through any other means.

Weaknesses.
Unlike their hive fleet cousins, they do not have the sheer mutability that the tyranids supply. Its really no loss thanks to the invulnerable save in my opinion!

Builds.
There are only two variables here. The first is the number of models to take, ranging from 5 to 20. Small squads can be terrifying and a decent distraction. Whilst large squads would be very nice in conjunction with the patriarch.

The second choice is whether to take scything talons. This provides an extra attack. Worth it for building pseudo-death star units.

Here's my two builds.

5 Purestrains (70 points).
The minimum squad with no upgrades can provide a nice fright to opponents. Particularly if you take multiple small units that are all infiltrating. This could be truly excellent. Heck, if you take an unbound army, you could fit at least 21 such squads in a 1500 point army (thats 105 genestealers for the curious). They will struggle against fliers, of course!

20 Purestrains all with scything talons (340 points).
The fully ungraded squad. Add in a Patriarch and you've got a super powerful close combat unit backed up with the psychic might of the Patriarch. Unsubtle and will rip through most enemy squads. You will still need other things for fliers and things like land raiders though.

Genestealer Cults Review: Hybrid Metamorphs

Background.
Mysteriously triggered when the hive fleets approach, the hybrid metamorphs feature the hybrids of the first and second generation combined with weaponry ordinarily associated with the tyranids themselves. These include items like bone swords that can really be very useful in close combat and others to boot.

Strengths.
The ability to take a mixture of different Tyranid upgrades is a strong one. However, my advice here is not to do much mix and matching within one squad in order to keep things very simple.

My favoured builds are noted below. But in short, I really like the claw option for the bonus strength and the lash option for the bonus initiative. I am not so sold on the talons really: the bonus to WS is somewhat wasteful in many situations.

For the leader upgrade, one is really paying through the nose to have a bone sword. It is worth it in my opinion, but only if you're going to have lots of other hybrids in the squad to ensure the leader makes it in to close combat with enemy squads.

The hand flamers are very nice, but might not be needed overall. I'd still be tempted to take a couple just for fun!

The cult icon combined with the talons might be good for excessive WS gain. But I'm still not quite sold on it unless you know you are going to be facing off Imperial Guard squads on foot. Let's face it -- they'll be in vehicles.

Weaknesses.
Toughness is still 3 here. The saving throw is still 5+. This is not good and they will perish quickly to small arms fire (e.g. Space Marines rapid firing their bolt guns!). This argues for larger squad sizes and tactical placement and use of this hard hitting unit.

Builds.
10 metamorphs, 1 leader with bone sword and whip, 3 others with whips, 6 with claws (138 points).
A rather nice melee squad to say the least. Some of the models strike first with the whips to give an edge over eldar, whilst the rest strike with a high strength to pile on the wounds. Take a transport to taste. (or drop a model to include an independent character to taste and put on board said transport).

5 metamorphs, 1 leader with bone sword and whip, 4 others with claws, all armed with hand flamers (108 points).
Expensive since this squad contains a lot of hand flamers. But with the right positioning, they will fry the enemy before charging in to finish off whatever remains. Cute, but unsubtle.

10 metamorphs all with claws (110 points).
Notice the points difference here compared to the above squad. With some good positioning and fortunate die rolls on charging and melee, they can crush a space marine squad through sheer number of wounds applied. Add in a goliath if required.

10 metamorphs all with whips (110 points).
Same price as the one above, but here to take out eldar enemy squads. Take a leader with bone sword to taste. Add in a goliath as required. 

Genestealer Cults Review: Neophyte Hybrids

Background.
Whereas the Acolyte Hybrids are the first and second generation of the genestealer infestation and infection, the Neophyte Hybrids are the latter third and fourth generations. Most are able to "pass" as true humans, although many still exhibit a forehead ridge and some skin pigmentation unbecoming of true humans. I'd dread to see Eldar or Ork hybrids of this stage(!)

Strengths.
Most obviously, these hybrids are cheap. Very cheap. And their units are very customisable. Combined with their special rules, they are very strong and very infiltrate-y and ambush-y.

Weaknesses.
In a nut shell, they have very mortal human statistics. That means "3" everywhere except for wounds and attacks. Admittedly, their leadership is a touch better than Imperial Guard, but not by much. And initiative can match a marine. That's from the genestealer side of the family at least.

Builds.
Oh boy. There are so many ways to build this squad its not funny. I'm going to provide a number of suggestions that folks might like to consider. There's no particularly correct way here, it all depends on how one is fielding the rest of the army, and what formations might or might not be in play realistically.

10 Neophytes, 2 mining lasers (80 points).
Few other units in 40k can take pseudo-lascannons for this points value. Plus stand a chance of getting them back thanks to their special rules. And infiltrate. Very nice indeed. Add in more Neophytes to taste. Or a Goliath.

10 Neophytes, 2 Seismic Cannon (90 points).
A similar build to the above but a bit riskier and more situational. A bit of a glass cannon really!

20 Neophytes, all with shot guns, 2 webbers (120 points).
A cute close assault squad. Take flamers instead of webbers if desired. Take a web pistol on the leader to taste.

10 Neophytes, 1 autocannon team (60 points).
A bit of a defensive unit really. Not sure I like it. Good for objective sitting. Add in 10 more neophytes and 2 flamers for insurance purposes!

Genestealer Cults Review: Acolyte Hybrids

Background.

The first and second generation of hybrids share more of their appearance with the genestealers than they do with the host species. Superhumanly fast, beastial, clawed, yet also able to wield weapons and guns thanks to their human heritage. They are an ungodly blend of species in short.

Strengths.

The acolytes are somewhat mutable in the sense that they can be built in a (small) number of ways. Plus, one can take mobs (is that the right collective word for hybrids? I'm not sure!) of up to 20 to scare opponents. But more fundamentally, these hybrids are good in close combat. Given their price tag, that might make them some of the best bang for their points value in the game realistically. 

They probably want to be either tooled up for close combat and in a large mob for use with some of the special genestealer rules and formations, or kept to ten or below models for use with Goliath transports. Either way, they are going to be solid in close combat and able to rip through most enemy squads. Think of them like orks -- but better. 

Weaknesses.

Poor save. Poor toughness. These are further reasons to buy in bulk!

Builds.

A few builds to consider.

20 Acolyte Hybrids, Leader with lash whip and bonesword (185 points).

For use with formations and genestealer cult special rules (cult ambush!).

9 Acolyte Hybrids, Leader with lash whip and bonesword (97 points).

Add in a Primus and a Goliath and you have a recipe for destruction. Add a rock cutter or rock saw to taste.

5 Acolyte Hybrids, 1 heavy rock drill (60 points).

A small squad for taking out tanks. Perhaps even road bumps. Several of these are rather scary when they appear rapidly all over the place.

10 Acolyte Hybrids, 5 hand flamers, 2 demolition charges (145 points).

Take a goliath. Throw the charges. Flame what's left. Return to the Shadows. Cult Ambush. Could be nasty. 

Genestealer Cults Review: Acolyte Iconward

Background.

Another new entry for the Cults compared to yesteryear, the Acolyte Iconward is a prime specimen of genestealer infection in an early generation. In his hands / claws / appendages is the icon of the cult -- a kind of inspiring sacred relic somewhere between religious icon and military banner. 

Strengths.

The Iconward has a slightly better statistic line compared to the ordinary hybrid (most obviously the extra wound). However, it is the presence of the banner that marks the Iconward out. The banner provides a large bubble of furious charge that the cult can take advantage of. In addition, he also provides a much needed bubble of feel no pain that at least can give a layer of protection to the otherwise rather poor 5+ saves that the army mostly has. 

Weaknesses.

Beyond these most obvious boons, the Iconward is not much to look at overall. 

Builds.

The only optional extra here is to take something from the relics list. I'm not sure its worth the investment overall to be honest. Hence my thought here is to just keep it simple and go with the basic build to save some points. 

Genestealer Cults Review: Primus

Background.

Although not making an appearance in the distant past, the Primus is a welcome addition to the Cults in the present day. Effectively, the Primus is the melee what the Magus is to the psychic phase. A specifically grown (or emerged) hybrid designed purely for strategy and acts of war.

Strengths.

The Primus has a reasonable profile apart from the Toughness (which remains at 3). His equipment is very reasonable with a combination of bonesword claws, toxins, needle pistol and so forth. This makes his a bit of a ripper in close combat and gives him something to play with at short range as well.

The real shining light here though is the bubble of hatred that the Primus can project. In concert with automatic look out sirs and attached to a large blob of hybrids, the Primus can cause real and significant damage to most things in the game.

Weaknesses.

Toughness is a problem. But remember that he has unquestioning loyalty to offset this. Plus the Primus is very cheap. At least compared to the Space Marine HQ selections that he can take down…

Builds.

The only option here is whether to give the Primus a relic or not. Personally, I think this one is about optimum if relics are anyway near tempting:

Primus with Sword of the Void's Eye (90 points).

With some of the other buffs available from other components of the army (e.g., Might from Beyond), this Primus is really able to take down most things in the game (or at least threaten them). Combined with the usual genestealer play style, this could be very deadly. 

Genestealer Cults Review: Magus

Background.

The Magus is a latter generation hybrid who is possessed of strong psychic powers. He has been in the canon since the earliest days of genestealer cults and is a mainstay for the force. Here in the modern edition, the Magus is illustrated as a psyker and leader in his own right. The modern take is therefore very much in line with what the figure should be: shrouded in mystery and masterful of the darker arts.

Strengths.

The most obvious strength of the Magus is his (her?) psychic powers. With access to the same disciplines as the Patriarch, it is almost a given that the Magus should be upgraded to a level 2 psyker, and should almost always be played alongside a Patriarch in order to dominate the psychic phase as much as possible. 

As with other leaders he projects a bubble: in this case adamantium will. This is a good boon, but maybe situational. 

Finally, the Magus gains access to the sacred relics of the cults. Some are good, others are a bit not so good.

Naturally, in the equipment department he comes with a force stave which will slowly but surely slay the opposition.

Weaknesses.

As with all of the other latter generation hybrids, the Magus features a predominantly human statistics line. This renders him very vulnerable. However, the automatic passing of "Look Our Sir!" with the unquestioning loyalty special rule means that when embedded in a large squad, he will survive a long time. Indeed, he has the potential to be a real unit slayer with the force stave in combination with the unquestioning loyalty rule.

Builds.

Overall, the Magus is really a quality denial unit, a decent tar pit when combined with large units, and one that can take out opponents given time and space. In terms of builds, it should be automatic to take a second mastery level. However, the other options can be interesting. Here are two builds to consider.

Magus with level 2 mastery (65 points).

This is what I would consider the base line.

Magus, level 2 mastery, relic: staff of the subterranean master (85 points).

Provides a nice bit of firepower which will come in handy against monsters.

Magus, level 2 master, relic: the crouchling, two familiars (95 points).

The Crouchling is a great option for the Magus as it generates a bonus power without increasing the mastery level. It provides extra attacks in close combat and with 2 further familiar, this makes the Magus strong in the mind and strong on the attack. 

Genestealer Cults Review: Patriarch

Beginning the reviews of the Genestealer Cults codex, we start the New Year with the Patriarch. 

Background.

The Patriarch is the genestealer that originally started the cult by ovipositor implantation of a victim. As the loyal cults grew around him (her?), their body swelled up to a larger size and their psychic powers burgeoned to a high. This entry in the codex is exactly what one might expect of a Patriarch: a massive genestealer that is superior in every way to a tyranid broodlord and even regular genestealers from this codex. 

Strengths.

With rending, shred and AP3, the patriarch is a deadly close combat exponent who will readily rip through entire space marine squads with embarrassing ease on the charge when accompanied by other genestealers. 

As if that were not enough, he's a psyker with biomancy, telepathy and brood mind powers. Indeed, the primaris power of brood mind can render the target squad horrendously unprepared for the coming onslaught. With invisibility, he's a terror that few will be able to match on the table top (and dare I even mention initiative = 7). 

The 12 inch bubble of fearless that he provides is a huge boon to the genestealer cults army overall which can be somewhat fragile in the face of aggressive incoming shooting. 

Weaknesses.

The patriarch does have a ballistic skill, but is unlikely to be doing too much shooting unless its a psychic power. His saving throw is literally mid-range as well. Watch the incoming shooting and play him (and presumably his brood) tactically by choosing your targets and getting the charge in as soon as possible. 

Builds.

Overall, the Patriarch is an excellent choice for the army and one which merits taking for most builds. 

Speaking of builds, there's a number of options to weigh up. Here's a small sample.

Patriarch (naked) (90 points).

With no upgrades, the Patriarch is still worth taking to say the least. 

Patriarch, level 2 psyker (115 points).

The second level of psionic activity ensures that he can cast some of the more powerful abilities. Certainly worth taking in conjunction with a Magus to ensure a solid psychic phase of the game.

Patriarch, level 2 psyker, two familiars (125 points).

The fully upgraded Patriarch realistically doesn't need the familiars. But they could be very useful if he detaches from a genestealer squad and charges on his own in to a squad he wants to rout off the battle.