Editing Warhammer 40,000/8th Edition Tactics/Space Marines (section)

====Imperium====
*'''Space Marines:''' You already know what's good since it's been discussed at length in the articles above. Make sure you account for their Chapter Tactics, as they may cause them to follow a very different playstyle than your own army despite having the exact same units available to them. 
*'''Blood Angels:''' The following 5 armies (lovingly referred to as other flavors of power armour) are mostly just your units mixed with some unique units and different chapter tactics. For Blood Angels, avoid melee if possible because they essentially get +1 to wound in the first round of combat. They often field lots of jump-pack infantry. Best known for their smash-captains, who rain terror down on battlefields everywhere- bring weapons that gain bonuses against things with the {{W40kKeyword|Fly}} keyword. 
*'''Dark Angels:''' They're the shooty emo catholic marines who are <s>secretly traitors hunting down loyal Dark Angels that they refer to as the Fallen</s> THE MOST LOYAL SERVANTS OF THE EMPEROR. Their Chapter Tactic makes them almost immune to morale, plus they re-roll 1s to hit if they stand still. They are less reliant on generic characters such as Chaplains and their Masters (the equivalent of Captains), but they do gravitate toward named characters a lot more. Their Chapter Master Azrael gives a 4+ Invulnerable save to all non-vehicle units within 6" of him, making him particularly annoying against weapons that rely on high AP in order to do damage. Their specialty is in Plasma, Biker Squads, and Terminator squads. Their most famous stratagem, "Weapons of the Dark Age", boosts the damage of all Plasma weaponry a chosen unit fields by 1. It is frequently paired with their Chapter Master Azrael leading a maxed-out squad of Hellblasters toting the Heavy Plasma Incinerators for devastating effect. Their Ravenwing units have a stratagem that lets them advance and still shoot and charge normally, letting them have a 4+ Invulnerable save against ranged attacks, and allow them to bring their assault Plasma Talons to bear. Deathwing Terminators are fearless, and can drop 2cps to shoot the moment they arrive from reserves in order to clear a screen and allow other deep-striking units to close in on you. The Darkshroud, another commonly seen unit, gives an aura of -1 to hit and can advance in order to get the 4+ Jink save like other Ravenwing units. Counter the Azrael-Darkshroud-Hellblaster-WotDA castle with Transhuman physiology to protect against the plasma, and bypass the Darkshroud's 4+ Invuln with the Flakk Missile and Hellfire Shells stratagem to whittle it down and drop it.
*'''Space Wolves:''' Like Blood Angels they are also a melee-centric army, with +1 to hit instead of +1 to wound. They focus more on running instead of jump-packing. This addition they gravitate towards weapons like power fists with a -1 to hit. Units of wolves and Thunderwolf cavalry are common to see. They are still Space marines and have a range of Shooting vehicles, flying landraiders and better devastators to fill in range. Their units of wolves provide nice chaff units. Outside of Thunderwolf and Wulfen spam, there's not a lot to see here. 
*'''Deathwatch:''' They're more elite Space Marines, who essentially have Sternguard Veterans as a troop choice and can gain bonuses against everything in a specific FOC slot. More importantly, they kept the Special Issue Ammunition that your veterans lost, which applies to all Bolter weaponry (minus Heavy Bolters and the Incinerator Heavy Bolters (Infernus Heavy Bolters)) fielded by their infantry and bike models.. They can mix Terminators, Assault Marines, and Bikers into said squads too, which is a funny gimmick. Their Watch Masters act like Chapter Masters, so be wary of an Intercessor blob with 5 hidden heavy hellblasters spitting out Hellfire rounds and S9 overcharged shots. They can deep-strike their entire army like Grey Knights, so a good screen and the Auspex Scan on a key unit of your choice should do well. Their Veterans like to hide Storm Shields in their squads to tank the odd Plasma gun or high-AP weapon shot, but with the new combat doctrines forcing a shit-ton of Bolter saves will hurt them, just as much as it does to your own units with Storm Shields. The Corvus is an overcosted flier just like your Storm Raven, a few Lascannons and multi-meltas will do you well. Again, using Transhuman Physiology against a unit's hellfire rounds will do you good, mitigating the 2+ to wound non-vehicle units.
*'''Grey Knights:''' Oh look, it's one of two armies that you can actually realistically outnumber (Knights are a third army you can outnumber, but they're tonka-tough). Let's be real: Grey Knights are long past the glory days of 5th Edition. Their equivalent units are either overcosted compared to yours or just flat-out suck, maybe with a few exceptions. Grand Masters in Dreadknights are one example, and the Chapter Master equivalent Kaldor Draigo is another one for the obvious reason. They can pull off decent alpha-strikes, but use Scout Squads and Infiltrators to zone out their deep strike bubbles and/or Auspex scan a unit of your choice. If you have access to Vanguard Primaris units, a couple combat squads of Infiltrators can not only block a Strike Squad out of Rapid Fire range, but also lock his entire army out of charge range. After that, it should be easy pickings as Grey Knights lack cost efficient means of mobility. Their interceptors are way too expensive for what they do and Stormravens are a major point sink that a few good lascannon and/or meltagun shots can swiftly take care of, so if you can hold onto the skies you should be in good shape. 
** I won't say too much here, cause I haven't read it in full yet, but Ritual of the Damned buffed these guys like crazy. Not saying they're game breakingly good now, but they're no slouches anymore. assume the above on Grey Knights isn't true, will update this when/if I get the book, or someone who knows more can update it. 
*'''Imperial Guard:''' Don't let their weak statlines fool you. Guard are VERY tough to deal with this edition. Between dirt-cheap infantry, extremely weapon-dense deep striking units like scion command squads, and absurdly good for their cost tanks, Guard can take an enormous beating and deal one out in turn. We'll point out the linchpin - ''Officers!'' Snipe out those low-wound characters to neuter the enemy chain of command and his infantry will suddenly be a LOT less impressive. Take a squad or two of Sniper Scouts or Eliminators. Vehicles to beware include the Leman Russ if it has the Conqueror Battle Cannon and the Executioner Plasma Cannon, Hellhounds, and any artillery vehicle. Now with the new codex and supplements (and the power creep that follows), we have LOTS of potential ways to counter the Guard's shenanigans, turnabout is fair play from their horrific index cheese. The Devastator Doctrine makes a mockery of guard tanks on turn 1, moreso if you're using Imperial Fists. The Tactical Doctrine will help you shred guard squads a bit easier (the guard player can't issue orders if there's nobody TO issue an order to), and the Assault Doctrine should be considered as a mop-up action. Consider taking Raven Guard Eliminators, and on turn 2 pop the tactical doctrine so you can snipe officers on 2+ (stick a Phobos Captain next to them to re-roll those pesky 1s), and deal mortal wounds on 5+. If you decide to wall-bang them with the Executioner Rounds you'll at least wound them on a 2+ and force saves. Thunderfire Cannons can shoot twice with the Suppressing Fire stratagem, enabling it to mulch 2 guard units in a turn (preferably any fragile Heavy Weapon Squad). A squad of 5 Reivers with combat knives and taking advantage of Shock Assault will throw out 21 attacks while lowering the Guard’s already weak Ld, wiping out entire 10-model squads in a single combat + morale.
*'''Adeptus Mechanicus:''' The weird middle-child between you and the Imperial Guard, Adeptus Mechanicus' can elect to run modestly cheap Skitarii-focused armies or eschew the tin men for the Cult Mechanicus tank-like Kataphrons. Either way, most AdMech players will likely be running their squads MSU style to get around their poor leadership. Weapons like Heavy Bolters strike a nice medium for ripping through most of their infantry, though you'll definitely want to pack a few Lascannons to handle any Dunecrawlers or Kastelan Robots. Other than the knights, not a single admech unit has t8, they also practically have no rapid fire weaponry and awful but universal invuls, making meltas a more or less perfect way to deal with most if not all their units. Don't underestimate the basic Skitarii though, their Arquebus sniper rifles and Plasma Calivers can easily chew through your marines if they get the chance, but thankfully they fall quickly if given any attention, which could be worth it anyway, considering that and their weapons cost a small fortune compared to other GEQ like units. Be aware that most admech armies have more than enough s6+ weaponry to chew through your marines, cover or not, if they don't have a better target, so bring vehicles to distract and counter the heavier elements while you play for objectives. Also, be careful when deploying and go for the second turn, they can and will happily kill or strand your marines and lighter vehicles if you are the first to break cover.
*'''Adeptus Ministorum:''' If you see someone using sisters at a tournament, be VERY afraid - sisters are one of, if not the, weakest armies in the current meta, so if you see someone using them in competitive play, they’re either insane or a tactical genius to rival Creed. This may change <s>when</s> if the new codex comes out, but for now if you face sisters take Centurions and any other mass-bolter fire unit.
*'''Adeptus Custodes:'''You will outnumber these golden boys, big time, but they are tough as nails and hit like a sock with a halfbrick. Best known for their jetbikes, which have hilarious amounts of firepower and are lethal in melee for good measure. Do not engage in combat if you can help it and bring as many sources of Mortal Wounds as you can. 
**At least until they get to bring Sisters of Silence along with them.
*'''Imperial Knights:''' Remember, Imperial Knights seem intimidating and are armed to the teeth, but they lack board control. If you have the second player turn, pop the Prepared Positions stratagem and watch as all your vehicles and infantry have 4+ saves against the Knights' Battlecannons! It's better than a 5 or 6+ save, after all. Lascannon spam, deep striking squads full of Meltaguns, or Chainfist Terminators can deal with Imperial Knights fairly well. As a general rule, Imperial Knights prefer their titanic feet attacks in melee compared to their arm weapons, aside from the Gallant variants. Best advice: play to the mission! Your best bet is to win on objective points, as most armies don't have the firepower to take down an army of knights. You can, however, wear them down enough to make them much less of a threat. 
**The basic Knight Paladin is armed with a Rapid Fire Battlecannon and the Reaper Chainsword, with two Stubbers. It's versatile, but a simple 2d6 Battlecannon shots is not quite as devastating as you think compared to its cost. The Imperial guard get 2d6 battlecannon shots on one battle tank that stands still, for 1/3 the cost of a Knight Paladin!
**The Knight Errant trades its RFBC for a Thermal Cannon that is half the range, but absolute cancer to vehicles and multi-wound models.
**The Knight Warden has a Thunderstrike Gauntlet and a RFBC base that can be exchanged for the Avenger Gatling Cannon, a 12 shot beast capable of reliably deleting your infantry units. 
**The Knight Crusader is the dakka knight, it has a Thermal Cannon (that can be swapped for a RFBC) and the Gatling Cannon.
**The addition of Armiger Knights makes things a bit more challenging as they can offer a bit more board control for the Knights at the expense of durability.  The Armiger Helverins are superior to Autocannon Predators every day of the week, and Armiger Warglaives that get too close will wreck vehicles and heavy infantry in short order. 
**The Dominus Knight variants are perhaps the biggest challenge. Both variants have weaker Battle cannons, and Shieldbreaker Missiles that can target characters, even out of LoS, for 2CPs. The infamous Dominus Castellan has a mini Volcano Cannon and a Plasma Decimator, it is capable of one-shotting two Land Raider equivalent vehicles per turn. Apologies Knight Crusader, THIS is the Dakka knight. The Dominus Valiant has a fuck-huge Harpoon that does a ''flat 10 damage'' and an additional d3 mortal wounds to a model that somehow survived the initial shot (Full strength Land Raider or Storm Raven). It also has a gigantic flamethrower for crowd control. The problem with the Valiant is that its weapons aside from the Shield Breaker missiles are so short ranged that you'll have a fairly easy time throwing enough meltagun shots and drowning it in mass bolter fire at it to destroy it. The same cannot be said for the long ranged Castellan who will try and play the keep away game.