Grey Knights

• Brotherhood of Psykers: All your Psykers get this, but otherwise it's your version of Chapter Tactics. You can add 1 to Psychic tests and Deny the Witch tests taken by your units. It also exempts you from the increased Warp Charge costs that would otherwise occur from casting Smite multiple times due to Psychic Focus.
• Knights of Titan: Objective Secured 8th Edition: if within range of an objective marker, you control it no matter how many of enemies try to swarm it, unless they have a similar rule, too.

Character Abilities of Grey knights

1. Daemon Slayer: If your Warlord wounds a Daemon in the Fight phase, your opponent must subtract 1 from any invulnerable saving throw against this attack. It's a little underwhelming, to say the least. Draigo has this by default.
2. Hammer of Righteousness: Add 1 to wound rolls for your Warlord if he charged that turn. Well, this one can be interesting on a Nemesis Dreadknight Grandmaster?.. Meh, scroll down. Crowe gets this by default.
3. Unyielding Anvil: Your Grey Knights within 6" of your Warlord auto-pass Morale. Kinda meh considering you play MSU with ATSKNF, but with the downgrade given to ATSKNF this edition, it is still ok. Stern has this.
4. First to the Fray: Re-roll failed charge rolls for your Warlord and Grey Knights units within 6". Very powerful, and saves a lot of CP. In fact, the question is: why even think of taking anything else instead of this marvelous piece of cheese?
   • Unfortunately, none of your named characters gets this. Always take a non-unique warlord to give this to.
5. Nemesis Lord: Add 1 to the Damage of your Warlords' melee weapons (generally becomes 1d3+1), reroll if he has a Relic of Titan as a melee weapon. Decent for a character hunter, but not much else. While this looks totally hilarious on an NDK grandmaster, don't fall into the trap of taking it over First to the Fray. In the long run, actually making it into CC will increase your damage output WAY more than +1D
6. Lore Master: Your warlord knows an additional power from Sanctic. Remember that "rule of one" in matched plays? You're better off with 4. Voldus has this.

Chapter Relic

• Banner of Refining Flame: Paladin Ancient or Brotherhood Ancient only. The model immediately loses the Rites of Banishment ability, and this time Smite drops to a pitiful 6" range, but always does D6 Mortal Wounds regardless of how high your casting value was. Takes the expected damage of Smite from the GK baseline of 0.83, past the standard output of 1.79, and all the way through to 2.92 expected mortal wounds. Stack this with a Brother Captain to deliver that at 12", not 6", so you can do it after teleporting in.
• Cuirass of Sacrifice: Requires the INFANTRY keyword, is not a suit of Terminator Armor like in 7th; 5+ FNP. Pretty great all around, since the 5+ works to prevent mortal wounds from Perils.
• Fury of Deimos: A souped-up Stormbolter and replaces one. 30", Rapid Fire 3 S5 AP-1 D1. Functionally worse than the Primarch's Wrath regular Space Marines get, since it is only D1 and effectively costs 2 points, rather than 0, but still the best weapons relic available to Grey Knights. You probably shouldn't take it.
  • Bolter Discipline does give it SOME new life for a Grand Master parked near some Purgation marines or a Dreadnought, but you're still wasting a slot best served on the Banner or the Cuirass.
• Destroyer of Crys'yllix: Souped-up (Plus 1D is NOT "souped-up") Nemesis Daemon Hammer and replaces one. Sx2 AP-3 D4, still subtracts 1 from hit rolls. Complete waste of a relic slot - GW has clearly established that relics should do more than merely add +1 damage, which has been everywhere else relegated to the "master-crafted" adjective. Do not take.
• Domina Liber Daemonica: All Daemons within a 6" bubble from the character must subtract 1 from their Leadership. What the hell happened? This thing used to grant an additional psychic power. Still fluffy, but with 6" area of effect, it isn't a game changer. The only relic a Grand Master in a Dreadknight can take, but just like others on this list, it will almost never benefit you enough to make it worth bringing.
• Soul Glaive: A souped-up Nemesis Halberd and replaces one. Improves the AP by 1, and rerolls failed hits and wounds. The re-rolling of wounds is the real kicker, and will actually get the halberd to outperform a set of falchions, but it won't get you up to Teeth of Terra levels, so, once again, just not good enough to justify a relic slot.

Strategems available to Deathwatch

• Honour the Chapter (3 CP): Use this stratagem at the end of the Fight Phase. Select a GREY KNIGHTS INFANTRY unit - that unit may immediately fight a second time. Literally a CTRL+C/CTRL+V of the Space Marine Codex rule. Use this on your Paladins, it will please you.
• Orbital Bombardment (3 CP): If your warlord didn't move in the movement phase, you can use this once per game in the shooting phase instead of having him shoot any weapons. Pick any spot on the battlefield that the warlord can see, and roll a D6 for every unit within D6", subtracting 1 if it's a Character. On a 4+, it takes D3 mortal wounds. It's another direct copy from the Marines Codex.
• Only in Death Does Duty End (1 CP): Use this stratagem whenever a GREY KNIGHTS CHARACTER is slain. That model may immediately make a shooting attack or a close combat attack. Note that this stratagem is half the CP cost of the Vanilla SM version.
• Wisdom of the Ancients (1 CP): Used at the start of any phase. Select a friendly GREY KNIGHTS DREADNOUGHT. Until the end of the phase, all friendly GREY KNIGHTS re-roll to-hit rolls of 1 within 6" of the Dreadnought. Again, a cut-and-paste of the Codex Marines stratagem.
• Tactical Flexibility (1 CP): At the start of your movement phase, pick a 10 model unit with the Combat Squads rule and split it into two 5 model units. Yep, another copypaste job.
• Armory of Titan (1/3 CP): Same as in every other Codex; use it before the battle and take an additional Relic (1 CP) or two (3 CP).
• Teleportarium (1 CP): You can set a GREY KNIGHTS INFANTRY unit or GREY KNIGHTS DREADNOUGHT in a Teleportarium chamber instead of placing it on the battlefield, essentially gaining Teleport Strike for 1 CP. Note that you can use it multiple times before the battle. This is super useful for getting Crowe and Purifiers closer to Cleansing Flame range. Or just cackle maniacally as you deepstrike Dreadnoughts.
• Truesilver Armor (1 CP): Activate when GREY KNIGHTS VEHICLE suffers a Mortal Wound: roll d6 for it and every subsequent Mortal Wound inflicted in that phase, on a roll of 5+ it is ignored.
• Psybolt Ammunition (2 CP): Used during the shooting phase. A chosen GREY KNIGHTS unit's Boltgun, Stormbolter, Hurricane Bolter and/or Heavy Bolter gain +1 strength and increases its AP by 1. So Storm Bolters become S5 AP-1, for example. Given how the Grey Knights' shooting has always been hampered by bad AP values, expect to use this a lot. Using this on a 10-man Strike Squad in rapid fire range will absolutely decimate hordes and even light vehicles like Raiders or Venoms.
  • Absolutely disgusting with the new Bolter Discipline rule, since you now get to have a greater volume of fire from greater distances. Who's got cripplingly short-ranged firepower now?
• Psychic Onslaught(2 CP): The same, but with Gatling Psilencers, Psilencers and regular and Heavy Psycannons. Psilencers become rather brutal against regular infantry and can even scratch high Toughness models due to number of shots. Best used on either a Purgation Squad with 4 psilencers or psycannons, or a Dreadknight with a Heavy Psycannon and a Gatling Psilencer.
• Psychic Channeling (1 CP):Used when taking a test for GREY KNIGHTS PSYKER. Roll 3 dice instead of 2 and pick 2 highest results.
• Teleportation Boost (1 CP): In the Movement Phase, an Interceptor Squad that has already made a teleport shunt can do it once again.
• Aegis (2 CP): Used in the psychic phase before a friendly GREY KNIGHTS unit attempts to deny the witch. They roll 3d6, picking the two highest when attempting to deny. Some Grey Knight veterans are still rather sore this is no longer part of the Special Rules.
• Heed the Prognosticars (2 CP): Used at the start of your turn. Pick a GREY KNIGHTS CHARACTER, add 1 to his invulnerable saves until the beginning of your next turn. Draigo with 2++? Yes, please!
• Mental Focus (2 CP): Used in the psychic phase. Lets a friendly GREY KNIGHTS unit try and manifest one more power. Practically useless considering your ratio of psykers to powers you're able to cast, and that's before you factor in the cost.
• Finest Hour (2 CP): At the start of your turn, double the range of any GREY KNIGHTS CHARACTER's aura effects.