Eldar Psychic Power tactics:

Integral to Eldar fluff and tactics are psychic powers. In 6th, Eldar have a lot more variety as far as available powers go in addition to a lot more potency/survivability in psychic offense/defense (compared to other psykers).  This is a rundown of how psychic powers will work for Eldar in 6th:

This post will deal with general changes to psychic powers/psykers in 6th, available powers and how they synergize with our army. Specifically, it will cover generating powers, casting powers, types of powers, Perils of the Warp/Deny the Witch/Psychic Hoods, codex powers Vs. rulebook powers and psychic power strategy. The beginning sections may be pretty basic and obvious to the more advanced players out there but I wanted to cover all the bases and make sure both new and veteran players reading my guides are on the same page before I delve into the more advanced tactics regarding psychic powers. Either way, it's always good to brush up on the rules!

Generating/choosing powers:

Before you can do anything with your psykers, you must figure out what powers they will have available each game. Psykers either generate/use their relevant codex powers as they always did or they randomly generate psychic powers from the appropriate rulebook disciplines available to them. This all happens in 1 of 2 ways:

1.) Use the available purchased codex powers and cast them as normal as per codex/main rulebook rules. For Eldar, this means that we can purchase, use and cast our codex powers like we always did such as paying 30 points for Fortune, 25 for Doom, 20 for Spirit Stones then casting both powers each turn by taking a psychic test for each power used (a psychic test is a simple leadership test).

2.) Before each game, generate powers from available disciplines in the main rulebook. This is done by exchanging all purchased powers for an equivalent number of rolls on the appropriate psychic discipline charts. This means that before each game you must choose to use the purchased/available codex powers or to exchange ALL purchased powers for an equivalent number of rolls in any combination of the Divination or Telepathy disciplines. For example, if you have a Farseer with 3 purchased powers, you can exchange them for 3 rolls on available psychic power charts in the available disciplines. Eldar only have access to Divination and Telepathy so you'd get as many rolls as purchased powers to divide up between either Divination and Telepathy as you wish. According to the FAQ, Eldrad can get 4 rolls when generating powers from the rulebook despite knowing 5 powers.

Casting powers:

Psykers in 6th all have something called a "Mastery Level." This level determines the number of powers they can cast a turn and most Psykers (including our base Farseer) are a Psyker Mastery Level of 1.

Based on our FAQ, it is presumed that Spirit Stones make our Farseers mastery level 2 allowing them to cast 2 psychic powers a turn. Eldrad is Mastery Level 3 so he can cast 3 powers a turn and I assume his staff still lets him cast one power twice. Also, according to our FAQ, Warlocks and the Harlequin Shadow Seer are Mastery Level 0 so they can't cast/generate any powers from the main rulebook but they still get our codex powers which automatically go off.

Types of powers:

There are now 8 types of psychic powers with slightly different rules/restrictions (none of which change how our codex powers work).They are: Blessing, Conjuration, Malediction, Witchfire. Witchfire has the following subtypes: Beam, Focussed Witchfire, Maelstrom, Nova. Confused? All you need to know about each is:

-Blessings are like many of our powers (like Guide), cast at the start of the player's movement phase.
-Conjurations are powers that cause units to move via deepstrike (like the telekinesis power "gate of infinity" which works like the Necron teleporty item) or powers that summon/create units (like the CSM Gift of Chaos power), also cast at the start of the player's movement phase.
-Maledictions (powers like Doom), also cast at the start of the player's movement phase.

Witchfire powers are psychic shooting attacks and are cast in the shooting phase. They need a roll to hit, unless they are a blast in which case they scatter and templates are just placed as normal and hit whatever is under them. The following subtypes of Witchire powers have slightly different/additional rules:

-Beam powers are like Bloodlance which are cast in a line from the psyker to a specific point/distance with the Strength of the power (if there is a S value) being reduced by 1 for every model hit beyond the first.
-Focussed Witchfire powers are like Mind War which, if the psychic test is 5 or under, the power hits the intended target otherwise it is a random member of the unit (Mind War doesn't need a roll to hit and as far as I can tell doesn't need a 5 or less on the psychic test to affect the targeted model).
-Maelstrom powers automatically hit all friendly and enemy units within the max range of the power, regardless of line of sight (but not those locked in combat).
-Nova powers automatically hit all enemy units within the max range of the power regardless of line of sight or units being in combat.

Worth mentioning is that the new Rulebook powers can target/affect allied battle brothers whereas certain Codex powers are only usable on our own units. Another biggie is that our codex powers specifically mention not needing line of sight so you can cast them on targets outside of a transport.

Perils, Deny the Witch, Psychic Hoods and you:
First off, "Perils of the Warp,""Psychic Hoods," and "Deny the Witch" rules have been changed/added to make psychic powers more dangerous to casting psykers as well as providing all armies with a universal defense against offensive powers.

Perils of the Warp:
Perils of the Warp is now an automatic wound with no armor or invulnerable saves allowed when a double 1 or 6 is rolled. What does this mean for us? Runes of Warding/Witnessing and Ghosthelms make Farseers the safest, most reliable and most dangerous psykers in the game. Specifically, ONLY Farseers can save against perils on a 3+ (thanks to Ghosthelm) and only Farseers can force enemy psykers to roll 3d6 added together causing perils on a 12+ (Runes of Warding). If you throw in Runes of Whitnessing where you roll 3d6 and take the 2 lowest results, you virtually eliminate your chance of rolling a double 6 but you slightly increase your chance of rolling a double 1. This can be offset by sticking the Farseer in a unit with Embolden as the Embolden power lets us re-roll leadership tests which include psychic tests (as per FAQ). 

Deny the Witch:
This is a 6+ save against OFFENSIVE psychic powers regardless of the source. This save can be modified to a 5+ if there is a psyker in the unit of equal or lesser mastery than the casting psyker and further increased to a 4+ if the psyker in the unit has a greater mastery level. To clarify, Deny the Witch will ONLY allow enemy units/psykers to try and nullify any power that harms or affects their own units, not beneficial powers that you cast on your own units like Fortune/Guide.

Psychic Hoods:

A Psychic Hood now only allows the model carrying the hood to make a Deny the Witch roll for units targeted within 6" of him. Models with a hood in a transport can only use their hood to protect the vehicle they are in.

Summary:
Between Runes of Witnessing, Embolden and Ghosthelms, we should hardly ever have to take Perils of the Warp wounds (excepting Psychout Missiles but we get Ghosthelm at least). Between Runes of Warding and Deny the Witch, we should make enemy psykers cry as they cast their powers on a 3d6 taking a perils wound on a 12+ in addition to being able to deny enemy offensive powers on a 4+ if a unit with a Farseer is targeted or a 5+ if a unit has a Warlock/Shadowseer in it. Now that I have talked about some psychic power basics, on to the psychic powers available to Eldar...

Codex and Rulebook powers:

Eldar Farseers (including Eldrad) have more options with the introduction of the rulebook psychic powers and both codex and rulebook powers offer a lot to our armies. The questions, then, are what powers to take and what do they do? I'll give a quick overview of our Codex powers along with the available powers from the rulebook then go into a tactical discussion on how to get the most out of the powers you do choose to take.

Codex powers:

We still have access to Fortune, Doom, Guide, Mind War and Eldritch Storm and these powers will still function the same way for our armies as they always have. In light of the available powers from the main rulebook, there are still three Codex powers that stand out as being very useful which are Fortune, Doom and to a lesser extent, Guide.

Fortune: 

This power targets a friendly unit within 6" of the Farseer and allows them to re-roll all saves, both Armor and Invulnerable. This is probably one of the best powers in the entire game as the only way to lose a model is to fail a save, re-rolling failed saves helps ensure your models die a lot less (duh).

Fortune turns a simple 66% chance to make a 3+ save into an 89% (I'm looking at Seer Councils on bikes and Wraithguard in particular). This power may also be essential for those of us that want to use Harlequins who will have a 2+ cover save instead of the way Veil of Tears used to work (they now get +3 to cover rather than 2d6 spotting distance, though the FAQ messed up and they technically get both but I anticipate that to be fixed).

Aside from the obvious benefit of being able to re-roll saves, why is Fortune almost essential for Eldar? I suspect Vehicles will become more fragile and used less frequently which means more anti-infantry weapons will abound. Have a certain scoring unit that NEEDS to live? Cast Fortune on it and weather the storm.

Doom:

This power targets an enemy (non-vehicle) unit within 24" of the Farseer and allows all friendly units to re-roll "to wound" rolls against the doomed target. This is probably the second or third best power in the game IMO because if you are shooting or attacking a unit in combat, "to wound" rolls are an essential part of causing damage next to "to hit" rolls which Guide and Prescience (powers I'll discuss later) help us with.

Guide:

This power targets a friendly unit within 6" and allows it to re-roll shooting "to hit" rolls. This is a very potent power for shooty units as a "to hit" roll is an essential part of doing damage to other units.

This power will take a back seat to the "prescience" power (which is found in the main rulebook) by virtue that prescience allows you to re-roll hits in combat as well as shooting. All of that aside, this power is still very potent for any shooty units you may have. Specifically, War Walkers, Falcons with Scatter/Cannon load out and EML/BL Wraith Lords benefit a lot from this power since you want to make their shots count.

The others:

Why not Mind War or Eldritch Storm? These other powers are situational/opportunistic by nature for what you get out of them and casting Fortune/Doom or Guide will usually do more for your army. If you take Eldrad and keep the Eldar powers, you get the latter 2 powers for free but will most likely end up casting Fortune/Doom or Guide more often than not unless you want to mess around with Mind War to take out a specific model or Eldritch Storm to turn vehicles to face a different way.

 If you are using Eldrad and have these powers with no reason to cast an extra Fortune/Doom or Guide then you will want to use Mind War on a targets equipped with P-fists/P-claws or special guys that grant Feel No Pain. Eldritch Storm is for Chimera walls/Battle Wagons that you want to turn and face in a way to give you side/rear armor for your lovely S6 shots.

Book Powers:

Thanks to the rulebook, we now get access to the Divination and Telepathy disciplines.The biggest question when generating powers from the rule book is whether to choose Divination or Telepathy? For me, the preference is Divination because there are more useful powers for our units than in Telepathy though Telepathy does have some nice powers but they are pretty situational. Depending on your opponents, you may want to take up Telepathy because of the offensive potential and I don't particularly recommend mixing disciplines unless you get the powers you want on your first few rolls in Divination. I'll discuss tactics in choosing powers and their uses more in the conclusion of this section.

The discipline of Divination: 

Erm, I mean divination...

This discipline functions much like our Codex Eldar powers, they buff our units and help you get the most out of them. All the powers cost only one Warp Charge to cast so a psyker with Mastery Level 1 can cast any of them. The number in the ( ) is the number you need to roll on a d6 to randomly generate the power.

Prescience: This power is a Blessing that targets a friendly unit within 12" of the casting psyker and allows that unit to re-roll all "to hit" rolls. This power is different than Guide in that Guide only works for shooting "to hit" rolls while this power also affects close combat attacks. This power, coupled with Doom, is amazing for any of our close combat units. This power is the discipline's "Primaris Power" and the only guaranteed power you can get in that you can exchange any generated power for this power. As a result, this power is not assigned a number like the other powers are as it can't be rolled for. 

Foreboding (1):
This power is a Blessing that targets the casting psyker and grants him and any unit he has joined the counter-attack special rule as well as allowing the unit to perform overwatch at the unit's normal BS. Cast this on a unit of Dire Avengers and let them counter charge whatever charges them as well as shooting (even blade storming) at the charging unit. This also makes Wraithguard/Fire Dragons very deadly as you can get a nice round of shooting off in your turn, cast this power on them and get another great round of shots. That will make what would otherwise seem like a no brainer charge something to think about.

Forewarning (2): This power is a Blessing that gives a friendly unit within 12" of the casting psyker a 4+ invulnerable save. This power seems to have been made for our Wraith units as one of the biggest problems for them was getting in combat with units that can ignore their armor saves. A fortuned 4+ invul on these units makes them virtually unkillable now. This spell has a lot of utility in that if you have a unit in particular you need to stick around, cast this spell on them with Fortune and you are set for life, yo. I am especially looking at the otherwise fragile and vulnerable to CC Guardian Jetbike unit in that you cast this power, Fortune and move 48" (yes our Eldar Jetbikes can turbo boost 48" a turn) to get an objective in enemy territory, having a re-rollable 4+ invul will really see them sticking around a lot longer.

Misfortune (3):

This power is a Malediction that targets an enemy unit 24" from the casting psyker that forces them to re-roll successful armor saves. How many times have you had an opponent that seemingly passed ALL their armor saves? This power will go a long way in skewing the dice in your favor. Like Doom, this power benefits your whole army against the target and when coupled with Prescience and Doom, Misfortune will see your army making units go away very effectively. This power is one you WANT to generate so cross your fingers as you generate spells!

Perfect Timing (4): This power is a Blessing that affects the casting psyker and any unit he is in and allows them to ignore cover saves. You have an enemy target that went to ground for a 2+ cover save? Cast this power and erase the unit with glee. This power basically gives any affected unit Crack Shot and makes Dark Reapers, Fire Dragons, Wraithguard and Dire Avengers especially nasty against a unit that will rely on cover against their shooting.

Precognition (5):

This power is a Blessing that only affects the casting psyker, it allows him to re-roll failed "to hit," "to wound," and any save rolls. Since this only affects the caster and since only Eldrad or a Farseer will have this power, there really isn't a huge benefit as Prescience/Fortune and Doom will most likely be in play anyway. This power should almost always be exchanged for Prescience.

Scrier's Gaze (6): This power is a Blessing that, as long as the casting psyker is alive, you can roll 3d6 and choose which of the 3 dice you want to apply to Reserve, Outflank and Mysterious Terrain rolls. This basically allows us to replace an Autarch in any of our "reserve denial" lists and actually provides more tactical options. I'd still exchange this power for Prescience unless you rolled Precognition in which case this spell provides more of a benefit if you have anything in reserves.

The discipline of Telepathy:

While this discipline has some spells that buff our units, it is mainly an offensive set of powers that can stifle an enemy unit's effectiveness and can really turn the tide of the game. Specifically, these powers affect enemy psychology/leadership so if you ever ally with IG and take a psyker battle squad, Telepathy is the discipline for you.. All powers except for Invisibility/Hallucination are Warp Charge 1 so casting Invisibility/Hallucination can only be cast by Eldrad or a Farseer with Spirit Stones (casting 1 of these powers basically counts as casting two normal powers). The number in the ( ) is the number you need to roll on a d6 to randomly generate the power.

Oh, you meant a Psychic Shriek, not Psychic Sheikh?

Psychic Shriek: This is a Witchfire that targets an enemy unit within 12" of the casting psyker causing 3d6-target's Ld value in wounds with no armor or cover saves allowed. This can be nifty if you manage to get the Warlord power that forces a unit to use the lowest Ld value in the unit (or have a psyker battle squad handy) but otherwise this is your own personal "doom of malantai" type of attack. This power is the discipline's "Primaris Power" and the only guaranteed power you can get in that you can exchange any generated power for this power. As a result, this power is not assigned a number like the other powers are as it can't be rolled for. 

Dominate (1):
This is a Malediction that targets an enemy unit within 24" of the casting psyker, forcing the target unit to have to take and pass a Ld test every time it wants move, shoot, run or declare a charge. This power has limited utility early on in that if a unit is embarked in a transport you can't target it but towards the middle/end of the game it will definitely come more into play as units will be shot out of vehicles and will start making their way towards objectives. This power has a nice synergy with the Terrify power that takes the Fearless USR away from a unit allowing this power to affect fearless units.

Mental Fortitude (2): This is a Blessing that targets a friendly unit within 24" of the casting psyker making the target unit regroup if it is falling back and also making it Fearless as long as the power is active. This power does for a unit what the Avatar fearless bubble does, including a 3" consolidation. This is nice for when you have that unit falling back with 1 model, rallying that model can prevent the enemy from getting a Kill Point (now called victory point) and allow the rallied unit to go on to either deny an enemy objective or claim one of your own depending on what the unit is. If you take an Avatar or don't care about models fleeing, this power should be swapped out for the discipline's Primaris Power.

Pupet Master (3):

This is a Focused Witchfire that targets an enemy model within 24" of the casting psyker and allows you to get a shooting attack with any weapon it has at a target other than the affected model's unit. It is not clear if this affects vehicles (I hope it does) and I am not sure how wonderful this ability will be though I guess getting a Missile Launcher equipped Long Fang to hit rear armor on some Rhino/Razorback could be cool.

Terrify (4): This is a Malediction that targets an enemy unit within 24" of the casting psyker which removes the benefits of the Fearless USR and causes an immediate morale check. This power works well with the #1 power Dominate as it allows Dominate to affect Fearless units. If you get a psyker battle squad from an allied IG detachment, this power along with Dominate basically take a unit out of the game for a turn, possibly even the rest of the game if they fail their morale test and break. No word on if this affects ATSKNF that Space Marines have. This power also allows the 1-2 result from Hallucination to affect Fearless units.

Invisibility (5):

This is a Blessing that targets a unit within 24" of the casting psyker which gives the target the Shrouded and Stealth special rules in addition to causing any units attacking or being attacked by the unit to be WS1 while this power is in effect (the WS 1 debuff only applies  to attacks made by or at the "invisible" unit, not any other unit attacking or being attacked in the combat). An added bonus is units charged by the target of Invisibility don't benefit from the Counter Charge special rule. This power is one reason to take Telepathy since it can give a skimmer that goes Flat Out a 2+ cover save or make any of our units hit opponent's on a 3+ while being hit on a 5+ in return. This power can cause that bad charge of Thunder Hammer Storm Shield terminators/Mega Nobs with Ghaz on a unit bounce off and do hardly any damage.

Hallucination (6):
This is a Malediction that targets a unit within 24" of the casting power and has a random affect based on a d6 roll in the following way:

1-2= "Bugs! I Hate Bugs!" which causes the unit to be automatically pinned unless it automatically passes pinning tests or is locked in combat.
3-4= "Ermmm?" which prevents the unit from being able to shoot, run, declare a charge or strike blows in close combat while the power is in effect.
5-6= "You! You're a Traitor!" which causes every model in the unit to inflict a single hit using base Strength but using any Strength bonuses/AP values and special rules of thier most powerful close combat weapon.

The first result specifically doesn't affect units that automatically pass pinning tests (Fearless units) but Terrify will fix that problem for you. The two other results can affect Fearless units just fine so this power is very potent and is basically a ranged Psychotrope Grenade that takes a psychic test to use.

Take a deep breathe, now we go into tactics and application...

Strategic overview of the disciplines/codex powers:
So now that you have a general idea of what the powers do, the question remains what powers do you want to end up with? That really depends on what your army looks like but I have a feeling many armies will end up with Eldrad and a Farseer being included in them. If this is true then I think we will still want access to Fortune and Doom; and, if you keep the Eldar powers on Eldrad you can get every Eldar power and cast them multiple times. This is why I am a strong advocate for keeping the Eldar powers on Eldrad, you get more use out of our codex powers with him. As far as the Farseer goes, it depends on how lucky you feel as I'd purchase 4 powers, Spirit Stones and Runes of Warding then hope for the best with my 4 rolls when generating rulebook powers.

As far as generating rulebook powers, I'd probably stick with Divination as they benefit our army very nicely giving us many re-rolls and I'd be hoping for the #3 power, Misfortune. This leads me to what I consider a "combo of doom" of psychic powers, that if cast together, will literally erase enemy units (two of these powers are in the Divination discipline).

These powers are Guide/Prescience, Doom and Misfortune. Guide/Prescience grant re-rolls on "to hit" rolls (with Guide only affecting shooting hits and Prescience affecting both shooting and combat hits); Doom grants re-rolls on "to wound" rolls; and, Misfortune forces an enemy unit to re-roll successful armor saves. Put it together and you will have tons of hits with tons of wounds with tons of failed armor saves=profit/win.

As I mentioned earlier, the Farseer with four rolls would go for Divination, having a good chance for you to generate the needed powers (prescience/misfortune) while being able to cast both of them a turn. The other powers are situational and are simply a nice bonus when you do cast them.

If you happen to get the powers I recommend on your first two rolls, by all means go for some Telepathy rolls and try the discipline out.

Certain units benefit more than others from certain psychic powers. Where this is the case, I will talk about this in the specific unit entry in later tactical articles. In the meantime, please give me any feedback you guys might have for this article and point out any areas that could use clarification/improvement.