Armoured Sentinels

Hi all,

I'll likely update this in the future, but I wanted to post some thoughts I've had about using Armoured Sentinels in particular. The scout variant certainly have their uses - but because they are so different, I think they deserve different articles. I also have some things I want to try out still, so this tactica primarily has things that I've already done.

Firstly, a look at the purpose behind the Sentinels (which is a good place to start before choosing any unit). They are generally fill a number of uses in my army, depending on the outfit.

1) Mobile armour defense. That is, defense of your own artillery, transport, and tank units. Because quite a number of vehicles have lower side armour values, it can be a great asset to put two armoured sentinels on the flank of the exposed vehicle I want to protect. The Sentinel armoured frame provides excellent line of sight restriction, particularly from enemy units that are firing from a higher position than the exposed vehicle (namely devastator squads, longfangs, pathfinders, lascannons, etc etc etc). If I need total protection, a small guardsmen squad can stand between the sentinels and the vehicle obscuring the vehicle from everything. Due to the range of the guns on the Sentinel they serve as a strong fire base - whislt at the same (if equipped correctly) understanding that the Sentinels aren't worth your opponents time taking out, my Manticore/Basilisk/Demolisher gets a 4+ cover, or 3+ with Camo netting, in the open. More on this later.

2) Anti transport defense. A number of weapon choices on the Armoured Sentinel are supurb at popping enemy transports as they close in. Lascannons, Autocannons, even multilasers all can achieve this. Because the Sentinel can move and fire, it isn't difficult to get into the side armour of that Chimera closing fast, or to negate the cover save of that Rhino trying to get through your lines. Again, the significant range of these weapons allows for a number of attempts to penetrate the vehicles. The Sentinels can also be upgraded with relatively cheap hunter killers, though I haven't taken these as of yet, and thus wouldn't go out of my way to recommend them (50/50 hit, one shot, I'd rather take a 10 point missile launcher in my chimera with my veterans that fires the same shot but regularly and accurately).

3) Anti infantry defense. A similar concept to the Anti transport, the Sentinels equipped with the Plasma Cannon can wreak havoc to approaching troops. Guard excel at laying down an impressive amount of blasts (which is the main reason I maintain Guard will always outshoot Tau). So make the most of this! I tend to favour the anti transport role, but fortunately, lascannons/multilasers/autocannons are also quite effective versing infantry, whether they get an armour save or not. (And obviously monstrous creatures often find themselves targets for these guns as well).

These first three roles work very well for Armoured Sentinels - at 60 points or so per vehicle, they are very cheap - they aren't open topped, and armour 12 is hard to beat. Due to the other vehicles in your army, most players will not attempt to shoot down the sentinels, provided they don't see them as a big enough threat. Number 4) is quite different though.

4) Assault capacity. Sentinels can move quite quickly - they can run if need be, they walk through terrain without risking being immobilsed, and they can shoot at the same time. Equipping Sentinels with flamers or plasma cannons, and walking them straight towards your opponents troops can do significant damage (depending on opponent). But their true value in the assault role is pinning enemy units in place. Without grenades or strength modification, your opponent isn't going anywhere. You need to be at least strength 6 to even glance these vehicles (hitting the front armour, as required when fighting mobile walkers), which means that orc charge just isn't going to cut it (let alone if you flame, then charge them yourself)!

Powerfists can cause you an issue, but if you think about it, two sentinels hitting a 30 man orc unit (thats 110 points versing 225 points), presuming you don't flame the opponent first, he can only swing that power claw at you. He hits on a 4+, so two hits being optimistic (with three attacks), say both penetrate, and he rolls a 2 and a 5. One is destroyed, the other one is sitting still. In his turn, he gets his three swings, and lets say he destroys you. He consolidates his unit 3 inches forward (rather than the 9 inch movement towards you) and you shoot him with the rest of your army. Or just assault another two sentinels in. (By the way, it generally can take them a lot longer to kill the sentinels!)

Grenades. Grenades are terrible at taking down Sentinels, unless your opponent has melta bombs (and then they are only bad, not terrible). Two Sentinels with multilasers charge a Space Marine squad. 6 shots, 3 hits, 3 wounds, 1 dead marine. You take a swing at him and achieve nothing. He swings at you - with 8 grenades and a power fist. He is using krak grenades - that's right, 6's to hit, and 6's to glance! Thats 1/36 chance * the number of grenades, or 8/36 (22%) chance of getting 1 glancing hit. Assuming he does hit and glance, he then has a 1/6 chance of scoring the 6 result, which immobilises, which destroys the first vehicle. Thats a 3.6% chance, and he has one vehicle remaining! Weapon destroyed results, stunned, or shaken achieve nothing for him (unless they eventually strip it down). You aren't going to be leaving the combat, so who needs a weapon? This is where the 10 point missile can come in handy - it negates a weapon destroyed result.

He then hits you with his Sergeants power fist - two attacks, say one hits, and he needs a 5+ to penetrate (even at str 8). He then needs a 4+ to destroy the vehicle (and you still have the other one). Thats what - another 22% chance of destroying the vehicle? And if he does kill one, it drops to about a 14% chance of killing the other. I have reliably held up Space Marine 10 man squads for 4-5 turns before he eventually rolls the lucky dice (and my opponent's army is in tatters at this stage).

5) Objective grabbers. Because a) your opponent doesn't tend to shoot down hard to kill vehicles that seemingly don't have the right weapon to hurt him, b) tend to leave their weakest and most vulnerable troops that don't have the powerfists etc behind their lines to hold their own base, and c) because your sentinels really are extremely hard to kill, should you manage to walk towards your opponent and one of his troop choices in combat towards the end game, that objective becomes contested - meanwhile, you've shot down everything coming towards your own objective, and you win the game! Sentinels just simply excel in this role.



Weapon options.

Multilaser - standard, cheap, 55 points. Multiple shot, best weapon verse marines etc where you don't ever intend to negate armour. Great for assault roles verse marines (or armies you can't shoot the troops down anyway) because it might kill a couple with 2's to wound. Also hurts monsters etc from range. Can punch holes in transports. Weight of fire second to none in the guard army with 3 shots per gun. B+

Autocannon - my favourite choice. Cheap, 60 points. FIres two rounds, achieves everything the multilaser achieves, slightly less likely to kill marines (hey, you really aren't going to kill that many anyway), great for pot shots on 4+ armour characters/meanies (orc nobs, fire dragons, etc). Also significantly more likely to hunt down those enemy transports, and far longer range than the multilaser! Wounds Monsters on 3's, not 4's, which kind of makes up for the lost shot anyway. To boot - because you are emptying less rounds (visually) into marines, as you move to charge and hold them up, your opponent really thinks you aren't achieving anything and will leave you alone (where as nine shots from three multilasers might achieve nothing, but attract attention!) I give this weapon an A++

Missile Launcher - a decent choice. One shot, which is good and bad, depending. The blast helps verse hordes (and even marines - more likely to kill), and you get an Ap 3 shot if you really need it. Slightly more points, more likely to penetrate a rhino, but less shots? I think the autocannon does it better. Same verse monsters - you'll probably wound on a 3+ anyway, so the two shots is better than the one. However, AP3? Can help. Missile Launchers are more attractive targets, but are more efficient in the anti infantry shooting role, without sacrificing too much over the multilaser and autocannon for versatility. A- weapon

Lascannon - I only field lascannons on Armoured Sentinels when I want Lascannon spam. Yes, they will hurt transports when they hit. Again, the autocannons with multiple shots can achieve the same thing. They probably won't hurt the armour 13/14 vehicles (they can hurt - but I'd use other more effective weapons). Lascannons are also targets - your opponent knows what you are doing when you field these. Lascannon spamming though can be effective - but I'd put lascannons in troops that can be twinlinked before putting them on my Sentinels. A bit more pricey than the other weapon options as well. There are a couple of redeeming factors - I've killed more than one character with this instant death cannon after blowing away his squad. No armour and 2's to wound really hurts! And a 4+ cover save isn't great - particularly when you get a chance to move so that he doesn't get the cover save at all. And these guns can be turned into marine killers - you'd think this is overkill, but when I really need to take out one more marine to cause fall back, due to already having dropped their leadership - it isn't so bad a choice. On the whole though, a solid B weapon.

Heavy Flamer - This weapon is good for the Scout, but terrible for the Armoured Sentinel. You kind of have the right idea when you are taking this option, because you obviously intend to assault (or counter assault), which is definitely my favourite use for Armoured Sentinels. But the heavy flamer actually becomes completely the wrong choice. Firstly, the flamer obviously has no real range - you are about to assault them when you get the chance to use this weapon. Your opponent knows this. Thus by equipping the heavy flamer, you have announced your intentions boldly and in bright neon colours even before the game begins. Secondly, when you flame, you likely will not kill very many of the unit you are attempting to take out (who cares really if you kill the one or two marines? Or even the 8 orcs?). Realistically, you are going to assault them anyway, and hopefully stop them moving - you don't need to kill them, because they aren't going to be able to kill you anyway.

What about troops on the objectives, I hear you protest? Wrong - again, the flamer announces your intention, and you draw fire to the sentinel before you even reach your target. The flamer may indeed kill the squad - but this isn't any good if you can't reach them. Secondly, do you really achieve anything by killing the squad, rather than locking it in combat? Think about Eldar rangers - with the flamer, you kill the squad, and contest the objective. Without the flamer, you don't kill the squad, and you contest the objective. Or you kill them anyway, because they lose combat sooner or later. You can be moving up troops yourself to take the objective - but in this case, your infantry's rate of fire will hurt them anyway, and most things you need a flamer for, you can mow down in combat.

For consistancy's sake, if you do bring a heavy flamer, I'll remind you you can only flame one level above you - so snipers sitting on the second level won't get touched. You can obviously move up the levels, but you basically need to be on top of your opponent in the first place to achieve this (in which you already should have assaulted them). Lastly, with the heavy flamer, you obviously lose the anti transport role, for little value in return. If you don't want to pay for weapons, take the multilaser instead. I give the heavy flamer a D.

Plasma Cannon - now we are talking. This is a great weapon - slaughters infantry (don't bother shooting tanks, it really isn't worth it!!), mobility to deny cover, running forward through the field to get better angles, long range. Great infantry defense when defending your vehicles. Awesome gun. What does this mean though? Awesome targets, as well. Your opponent will attempt to sink these babies with their heavier guns - particularly when you have a squadron of them. They are pricy, and when they are putting out the fire power of some of your other armour 14 tanks, you easily become a priority. You also aren't as effective in the holding up infantry role - because you want to shoot them! You won't opt to run, and (though I haven't been put in this situation yet myself), I imagine I wouldn't opt to assault when I could shoot instead. So you kill a few marines, they get past your lines, and you've missed your chance to hold them up. Great weapon, great defense, loses out on the more awesome role of stopping your opponent in his tracks though - and also isn't worth killing enemy transports with (which conveniantly also stops the enemy reaching you!) If I field a Plasma cannon, it is a distraction for my opponent, I sit back and shoot, and I probably have other Sentinels moving in to hold my opponent down for a thrashing. I give this weapon a B+ on the basis that I believe the assault role is the better choice for the Armoured Sentinel.




A note on squad size - I often field one or two sentinels in a squad, and rarely three. One for units that will attract attention (plasma cannons), as I don't want my opponent killing all of them in one round. Two for assault roles - if one gets taken down, the other becomes more effective. Two for giving cover saves, as you need to cover the majority. Two for giving myself maximum armour protection - if a sentinel is facing one way, and the other is facing the other, with a 90 degree angle between the facings, your opponent always determines armour facing from the closest model, and thus you maintain armour 12 on both flanks. I'd need a good reason to field three - I think they would quickly become targets.


I love Armoured Sentinels. I laughed for joy when I found out they were being released - I already used regular sentinels to pin my opponent, and these just make it ridiculously easy for a very cheap price. I've won many games simply with the tactics above, whilst the rest of my army pounds my enemy to dust. They are great for changing roles as well - a moving defense for your chimera, holding your troops, providing a cover save to another troop squad covering the bottom half of the chimera, walking towards an objective, shooting up enemy transports on the way, moving in to engage any assault troops that get in the way, or pinning your opponents troops in combat when your convoy reaches the opponents objective? These units are gold. However, know what they can and can't do - melta bombs will kill, melta guns will kill. Multiple multimeltas, will kill! And keep in mind your side armour is still 10 - you can get destroyed if you are careless and expose yourself to strength 6 side shots. Know what you can do with these vehicles, and they can change your Guard experience.

Some last thoughts as well - I haven't done this yet, but it is on my mind. A guard army tooled up with psykers, blasts, pinning, snipers, griffons etc, with Armoured Sentinels, should be very effective. Shoot and pin the non-fearless units. Charge the other units that get close. Stop your opponent from moving in.

A similar strategy, that I again have yet to try, is fielding a vindicare assassin that shoots down anything that can hurt your sentinels in combat, with you fielding 3 armoured sentinel squads of 3. Imagine that space marine sergent with power fist getting hit by a 2+ to hit, 2+ to wound, ap 2 round, that at most, gives him a 5+ cover save. Or hitting the orc power claw, 2+ to hit, 4+ to wound, AP 2, and causing 2 wounds. The biggest problem with the vindicare is that with only 5-7 rounds, you can only fire 5-7 times; but this tactic may make it worthwhile, if half of those shots effectively removes an entire unit from play! I'm working on a number of ideas that I'll incorporate into a Vindicare strategy, and post later this year with its effectiveness - but something to think about. (By the way - this could really, really be awesome in planet strike - as defender, you can have a bastion that allows a unit inside to reroll hits and wounds, and your opponent needs to get to your objectives at all costs - 2+ to hit, 4+ to wound with rerolls? Easy as pie).

Thanks for reading, feel free to comment! Scout Sentinel strategy coming soon.

Manticores

I recently took two Manticore artillery pieces to CanCon, and was truly suprised by the results.

Firstly, an explanation of their weaponry. A Manticore fires between one and three large blast templates, either directly or indirectly (barrage), with the highest strength in the game, and ordance to boot. Whilst they won't breach space marine armour, the sheer amount of wounds these tanks can generate really packs a punch.

Firing indirectly against units that aren't in area terrain, but have both intervening cover and an insufficient armour save can absolutely destroy the unit/s. We're talking Orcs, Eldar, Tau, Tyrannids, Guard, etc... You fire using the multiple barrage rules, and if you can still draw line of sight, then you can subtract your ballistic skill for the initial round. Just remember, you can't move when firing indirectly, and don't forget the minimum range.

Firing directly is absolute gold against anything that has sufficient armour save not to need cover. You still fire one to three shots, but you don't use the multiple barrage rules - instead, you resolve each shot separately! Thus you can maximise wound potential, subtract your ballistic skill from all shots fired, and you can move from hiding into line of sight, for a very suprising volley! Firing directly also conveniantly ignores the minimum range rule.

When shooting at vehicles. Obviously, if you can, fire directly in all cases - if they aren't going to get a cover save, or use a cover save, then this is by far the more accurate option. However -- when shooting at any vehicle that is in cover with intervening terrain, the manticore effectively ignores the coversave! Try to draw any line of sight if possible (remembering you can rotate but not move) in order to subtract ballistic skill from the scatter, but realistically most medium to large vehicles you should hit. Because barrage hits the side armour, this often will instantly penetrate (rolling 2d6 pick the highest), and there is always the potential for multiple hits from the one shot.

Don't forget that when the centre of the hole is not over the enemy vehicle (thus making you half strength), you still roll 2d6 for armour penetration. If the side of the enemy vehicle is 12 or less, you can still cause a lot of damage (very helpful for those blasts that scatter!)


A number of other advantages/tricks with the manticore.

- The manticore also pins enemy units at -1 leadership - given that it is a barrage ordanance weapon. Versing Space Wolves that were lead by leadership 8 Wolf Guard, I believe I pinned a total of 6 enemy units during the course of the game! (Without any other penalties to leadership). Because the Manticore is nearly guarenteed to cause at least a single failed armour save, this can be effective (as well as combined with Psyker squads and other tricks).

- The manticore also generally causes instant death. Tyrannids in particular are no longer immune to this - and as it typically pierces their armour, this can be devastating to warriors and what not. Also, the ability to do so many wounds, and force armour saves to be taken across the board, means you have the ability to wipe out space marine (and other) heroes with ease - if they fail that armour save, they aren't getting up.

- Tau have a technology that makes their vehicle count as obscured when the enemy is firing from more than 12 inches away. However, the barrage rules state that you resolve the shot coming from the centre of the hole, rather than coming from the firer - so this rule is ignored when the Manticore is firing indirectly.

- Those unkillable monoliths? Firing a manticore directly gives you a pretty good chance of hurting it. Each blast is very likely to hit, due to the size of the monolith, and penetrates the vehicle on a 5+ (rolling 2 dice) - not bad! That's what - 55% chance for penetration with each hit? And a 2/3 chance of getting at least a glancing.

- The manticore can be extremely effective when shooting at Walker squadrons. I had one direct hit on the centre walker of a squadron of three - and even though my blast was half strength on the other two, I penetrated and destroyed all three walkers (rolling 2d6). This was helped by only needing a 4+ to destroy them, thanks to the immobilise/squadron rules.


The manticore truly is a marvel - with the ability to destroy enemies without being in line of sight, obliterating both enemy vehicles and infantry, with stronger armour penetration than a Basilisk, more fire power, and the overwhelming use of cover these days, the Manticore is a must-have. Almost every single opponent that I played in the tournament commented on how destructive these units were.

Battle Psykers with the Inquisition

- Inquisitor, Psychic Hood.
Drop the leadership of an enemy psyker when you have first turn. As the power lasts for the entire turn (not player turn), your opponent's leadership is still worthless in his phase. When he casts that power, you can stop it with ease. This is very effective verse eldar, slannesh and the like.


- Inquisitor. Divine Pronouncemnt.
This power is devastating when combined with your psyker battle squads. Your opponent must take a leadership test, with a penalty of the difference in respective leaderships, or immediately fall back. As guard tend to park near their objectives and shoot, when your opponent is running towards you, you want them to go away! This power virtually ensures that this will happen. This power is also amazingly effective when your psykers have burnt out a bit - with only 2 psykers left due to perils, dropping a leadership 9 unit to leadership 7 means they are now leadership 4 when facing Divine Pronouncement - how awesome is that? This is a great defensive power.

Furthermore -- if an opponent is already falling back, they automatically fail a moral test if they are forced to take a second one (apart from pinning, which they ignore/continue to fall back). So conceivably you could tank shock a unit into running, cast divine pronouncement on them to make them immediately run again, and shoot 25% of the unit down to force up to 6d6 inches of movement away from your objective! I haven'd done this with the tankshock, but certainly divine prouncement and shooting combined can truly be devastating. And when those units flee 3d6 naturally (bikes, jump packs, etc) they aren't going to be on the board for very long...


- Inquisitor. Purgatus.
This is a good power for destroying single characters that really give you a headache. Picture the space marine special character who gives his entire army his leadership. Drop his leaderhip to 4, then hit him with purgatus, and make him run. This power is also extremely useful versing other psykers - drop the leaderhip of that farseer with your psyker battle squad, hit him with purgatus, and your psychic hood will always stop their powers from now on (Fortune? Hahaha).


- Inquisitor, Hammer of the Witches.
I've taken this power for virtually the sole purpose of annhilating Seer Councils, which I find very annoying to play against. But it also works great against Tyrannids (and with the new codex just around the corner...) Drop the leadership of a psyker squad (or individual psyker if you must) and watch them squirm. No range limit, no line of sight required - I burned an entire seer council (all the warlocks died) with this power. Tyrannid Warriors lose half their unit every time. Orc weird boy sniping action, you get the idea! Of note - yes, it is difficult to get powers through Eldar defense, when they make you roll 3d6 - but it is somewhere around a 33% chance of successfully casting weaken resolve per unit, and 50% chance of casting hammer with your inquisitor, so 2 psyker squads will be successful perhaps 40% of the time you attept this (and you can attempt it a few times per game). So don't be too afraid to try - that seer council is worth far more to them than your psykers are to you!


- Culexus assassin.
The obvious - cheesey plus when you get assault 2 + 1 for every psyker in range. You can't really use your powers here (well, try if you want I guess), but this little beauty will kill anything in short range when combined with your psykers.


- Callidus assassin
By far my favourite, and I think far more deadly than the Culexus. Firstly, a word in your ear - move your opponents troop choice as close as you can to the board edge, drop their leadership, and force them to fall back! Particularly if you have first turn, this is a nightmare for any non-fearless unit. Secondly, the flamer attack of doom. Str 8 AP1 vs your opponents leadership. Drop that leadership 10 unit by 6, flame them, and instant death on 2's! Particularly as you appear anywhere you want on that battlefield. Also, remember to deploy both where your flame is effective, where you can be hidden from enemy shooting in the next turn, and (if you expect your opponent to run) inbetween the unit and his table edge - your oppoenent will have to run past you, and thus remain within 6 inches, not being able to rally in his following turn (very effective vs space marines!). Also note, you may still drop an opponents leadership, even if they are fearless. For example, that huge orc unit that is leadership 10 fearless, drops to leadership 4 fearless, and thus is toast vs your flamer. Even with 2-3 psykers left after perils, you can annhilate entire units. I use the callidus to clear out enemy objectives that I can't get to (again, focus on killing their troops where possible).

Battle Psykers in a Guard army

I don't know why more people don't use psykers. They are truly awesome for their potential + point costs, and have won me many, many a game. Both powers are extremely good, have incredible range, and can destroy most non-vehicle units in the game (for under 100 points a unit)! This post goes into some general ideas about the unit, and some incredibly powerful combinations - inquisitors, assassins, demon hunters and more.

The composition - depending on what you are going for, my standard is 5-6 psykers + overseer. Please note, the overseer is not a psyker, and does not contribute to the psyker powers. A chimera allows a great fire base, and you can still use the weaken resolve power if the vehicle is stunned. However, 5-6 in the open isn't bad either, as you can hide them and move a single model to line of sight of the target, without confering a cover save to your opponent (the attack is worked out from the single psyker only). I generally choose 5-6 as it gives you room for losing a few due to perils, or having a few shot up. It isn't a huge number to be a points sink, and generally you don't need more than str 6 or -6 leadership penalty to achieve what you want to do (assuming you are using them properly).

Applications

The bomb. With AP D6, they have a 50/50 of annihilating space marines, and 1/3 of going AP 2. With two squads at strength 6, that is something to be reckonned with! Considering the massive range, these psykers can engage from the first turn for tremendous damage. Use the weapon against mass targets, not large single targets (which is why i prefer the 5-6 rather than the uber str 9). Don't bother targeting vehicles, you have other things that can do this. Though I think the second power is far more devastating, the bomb is an awesome fall back power - so what if your opponent is fearless? Demons dying on 2+ to your str 6 blasts? No problem.

Weaken resolve. Dropping an opponent's leadership for pinning, falling back and rallying. Generally in games my overall strategy is to destroy anything they have that can win the game. Consider two psyker squads dropping two enemy units leadership values. Now combine that with the humble mortar. A single hit wounding space marines on 2's, and suddenly they are pinned unless they beat a leadership 3 roll? 2 Lascannon wounds from that Vendetta of yours suddenly causes a space marine unit to run off the table in the first turn? Or something even more sinister? Weaken resolve truly is game-breaking. Your focus generally should be on annhilating the enemy troop choices. Some ideas to think about --

a) Pinning. Simple - a senior command squad tooled up with 3-4 sniper rifles. Mortar Heavy Weapon platoons. Griffons (reroll barrage you say, at str 6? for 75 points??). Manticores (-1 to their leadership for pinning). You shouldn't be using ratlings, because you have Psykers instead! But most importantly, every time a unit causes a pinning test, they have to immediately take a test - even taking multiple tests in the same turn. All you have to do is wound your opponent, and they are stuck in place.

b) Fall back. In my current list, I field as many high powered guns with long range that I can. Autocannons, lascannons, griffons, manticores, multilasers, heavy bolters, etc etc. Your goal is to kill that magical 25% of the enemy unit to make them break. With lowered leadership, most armies will never rally (keep in mind that if you go first, the power lasts for the entire turn - in your opponents turn he is rallying at -6 to his leadership!!). Making a unit effectively fall back between 2-4d6 removes them from the game, particularly early on. I find Vendetta's in particular very, very effective in this role - not much can stand up to 3 twinlinked lascannons. Kill that 25% and they aren't coming back. Intercepting works as well, particularly later in the game - your sentinels outflank at just the right spot to make your enemy unit keep running (even space marines can't rally if they are within 6 inches of an enemy). Target priority is also very important - early on, you want to kill their troops. Hit them while they are in the deployment zone still! They'll very quickly lose 1-2 units that they were counting on, and begin to play for the draw. Keep in mind that jet packs, bikes and the like fall back 3d6 -- these should be targeted later (though before they reach you).

- Primaris Psyker, shroud
I haven't attempted this yet, but it seems solid in theory. Attach a primaris to a unit you really want to keep alive. Ie, rough riders, huge guard squads, units holding the objective to the death, etc. If you succesfully cast the shroud, all enemy units need to take leadership test to be able to shoot you! With two-three psyker battle squads on the field, you can force your opponent to really think hard about whether he will take the risk or not. Keep in mind this doesn't protect you from vehicles - but if you combine this with blocking line of sight, you should be able to keep a fast flanking unit very safe indeed.

Concluding thoughts --- Psykers are awesome. They can destroy your opponents army, your opponent begins to fear them above all else and tries to take them out as fast as he can - leaving your troops alone to win the game. My units cost only 135 points with Chimera gun platforms, which only enhance their effectiveness (all powers and guns are the same range). Again, weaken resolve is not a psychic shooting power, and thus can be used even if you have moved 12 inches or cannot shoot that turn. There are probably many more things that you can do with these guys as well - and when your opponent says 'but my units are fearless', hit them with the bomb, or drop their leadership anyway and let the callidus do the work.