As I said, there is so much new stuff with 8th edition, it has been hard for me to know where to start.
With the Grey Knights Codex about to be released, however, and the Knights of Titan being my first 40K army when I started the hobby, I am quite excited about the rumors for their book and thought I’d start here by talking about some potential tactical combinations they can use:
 “Smite Storm” Battle Group — Take Crowe, two 5 man Purifier squads, a Brotherhood Ancient (with the new Relic Banner), and Brother-Captain Stern and load the whole shooting match into a Land Raider Crusader (which is now MUCH more survivable than in past editions, with T8, 16W, and a 2+ save, meaning that it is very likely to get across the battlefield successfully and deliver all of its passengers, compared to the past where Grav and Melta could easily kill it in a single turn).
Turn 1, cast Gates of Infinity on the LRC and teleport it 9″ away from enemy lines (yes, believe it or not, the wording of Gates of Infinity means you can use it on vehicles… it only says “GK unit,” not “GK infantry”… hence, teleporting Land Raiders), then unleash up to 28 bolter shots (Hurricane Bolters plus SB upgrade) and 12 assault cannon shots (plus a MM if you took that upgrade), all firing at full BS, thanks to POTMS. Turn 2, disembark all the passengers 3″, then move them up another 5-6″, putting Purifiers/Crowe/Stern/BH Ancient all within at least 6” of the enemy(s) unit you want to “nuke” (i.e. say it is an enemy Imperial Knight or Guilliman or a Stormsurge or some other kind of very tough LOW unit).
In the Psychic Phase, Crowe and both Purifier squads can unleash their “Cleansing Flame” version of Smite (with a range of 6″, thanks to “doubling” effect of Stern’s Psychic Focus ability). Additionally, the BH Ancient can use his Relic Banner to cast his enhanced, D6 Mortal Wounds version of Smite as well, Brother-Captain Stern can cast “regular” (i.e. only one Mortal Wound for GKs, due to Rites of Banishment) Smite, Crowe can use his second power to cast Vortex of Doom, and Stern can use his second power to cast Purge Soul (using his Ld9 +1 from the Ancient’s Banner, for a total of Ld 10).
The new “Brotherhood of Psykers” rule gives all of these GK units +1 to their Psychic tests, meaning that for all the variations of Smite they only need to roll a 4, for Purge Soul Stern only needs a 4, and for Vortex of Doom Crowe only needs a 7, all of which are quite achievable with average rolling. Against opponents without any Psyker support (like Tau or Dark Eldar or pure Imperial Knights, plus lots of other armies these days, now that the Psychic phase is no longer so dominant and many armies run without any Psykers in their ranks), there is no way to reliably stop all of these GK powers if they are cast successfully.
What all this means is that, given that all these powers go off, they cause 4D6 +1 Mortals Wounds from all the different Smites/Cleansing Flames, another D3 Mortal Wounds from Vortex of Doom, and then potentially even more Mortal Wounds if Stern wins the Leadership test against the target with his Purge Soul. Using a Tau Stormsurge as an example (which has 20W at T7/3+/4++ with the mandatory Shield Generator and has Ld8), the combination of all of these powers going off in a single Psychic phase would strip an average of 17 Mortal Wounds, leaving it with 3W remaining and only able to shoot at BS6+. Throw in the 52 Storm Bolter shots from all of these GK models and you should be able to strip off those remaining three wounds with average rolling, thus leaving the five different GK units free to assault other elements of the Tau gun-line, if necessary (and this of course doesn’t count the shooting from the LRC either).
 “Fire Base” Land Raider — As in previous editions, it appears that one of the weaknesses of Grey Knights is their lack of long-range firepower, especially against high toughness Vehicles and Monsters. One possible way to mitigate this is to take a Void Shield Generator, a GK Land Raider (standard pattern with four Lascannons, two HBs), and a GK Grand Master with the new Sanctuary and Astral Aim powers.
Hide the Land Raider and Grand Master behind the Void Shield Generator to block LOS from enemy shooting and then cast both Sanctuary and Astral Aim on the Land Raider… this gives the tank a 2+ Armor save and 4++ Invul save against any units that are able to gain LOS on it (or that are able to maneuver into LOS via Deep Striking, such as Tau Commanders, MT Scions, Drop Podding Sternguard with combi-Meltas, etc.) and then also allows the Land Raider to shoot at enemy units within range (48″ for Lascannons, 36″ for Heavy Bolters) without actually having to have LOS to them.
Finally, the Land Raider shooting also ignores any enemy Cover saves, thanks to Astral Aim, and gets to re-roll 1s to hit, due to the Grand Master’s Rites of Battle aura, making it more accurate/reliable (the Grand Master also provides some solid “counter-assault” capabilities, should enemy assault forces get too close to the Land Raider). Good enemy targets for this tactic likely include multi-wound, durable squads (like Tau Battle Suits, Primaris Infantry, Craftworld Wraith units, Drukhari Grotesques, Necron Destroyers, Space Marine Terminators, Mega Nobz, etc.) and light/medium vehicles, which the 4 Lascannon and 6 HB shots a turn can all do solid work against.
 Draigo/Stormraven “Dakkaboat” Tactics — Take Kaldor Draigo and a GK Stormraven with Twin Heavy Bolter, Twin Assault Cannon, two Hurricane Bolters, and two Stormstrike Missile Launchers. Turn 1, “dash” the Stormraven up to 45″ forward to get it within 12″ of the enemy battle line and then, at the end of the Movement Phase, Deep Strike Draigo in so that he is within 6″ of the Stormraven (and also so that the Stormraven is closer to the enemy units than he is, meaning they can’t shoot at him except with Sniper weapons).
Use Draigo to cast Sanctuary on the Stormraven (giving it a 3+/5++) and then, at the beginning of your shooting phase, use the new “Psybolt Ammo” Stratagem to power up the Stormraven’s shooting (‘i.e. all Bolters, Heavy Bolters, Storm Bolters, and Hurricane Bolters get +1S/-1 AP for the phase). This gives you a total of 24 x S5 AP-1 Hurricane Bolter shots, 12 x S6 AP-1 Assault Cannon Shots, 6 x S6 AP-2 Heavy Bolter shots, and 2 x S8 AP-3 D3 shots at an enemy unit/units within 12″.
Combined with POTMS (so no penalty to shooting Heavy Weapons because the Stormraven moved) and Draigo’s “Chapter Master” aura granting re-rolls to all to Hit, this gives the GK army the ability to put out some serious damage against massed infantry and even light vehicles. For example, against the current “conscript spam” found in many competitive AM lists, a Stormraven using this tactic would average about 20 unsaved wounds on a conscript blob. Add in Draigo’s Storm Bolter, Smite, and Vortex of Doom powers and you can realistically kill up to 26 conscripts in a single go … if Draigo then successfully charges the 4 remaining conscripts, he should easily wipe them out, thereby completely removing your opponent’s “bubble wrap” in a single turn and opening the way up for more GK units to Deep Strike/teleport in and get into assault with the rest of his army.
Alternately, if you apply this tactic to the following units, here is “average” casualties:
-30 Ork Boyz — 29 Unsaved Wounds
-20 Necron Warriors – 22 Unsaved Wounds
-6 Devastator Centurions – 12 Unsaved Wounds
-10 Craftworld Wraithguard – 16 Unsaved Wounds
-10 Primaris Intercessors — 18 Unsaved Wounds
As you can see, against a whole variety of infantry targets, this tactic can put out a very significant amount of damage and take a large chunk out of your opponent’s combat power in a single turn of Psychic abilities/shooting.
OK, well, enough for now, but I will continue to look at Grey Knight abilities and synergies, especially once the new book comes out later this week, and in the future we will see what other ways the “boys in grey” can win the day for the Emperor on the table-top.