This guide was written entirely by /u/Ronar123 on the XCOM subreddit.

Hello everyone, I occasionally see questions regarding how to succeed in XCOM 2's Legendary difficulty so today I am going to do a write up on all the steps to being able to consistently handle the hardest difficulty of this game. This guide is particularly for those who are seeking to transition from a lower difficulty to Legendary. Whether you're a long time Commander player or just starting out from Rookie, this guide will help you take your campaigns to the next level. I find that discussions are sometimes divided between Legendary players and casual players who don't have as much time to learn the mechanics of this game. My goal is to bridge the gap in knowledge between the difficulty levels and hopefully allow even more players to join in on the fun of intensive Legendary campaigns. Now let's get started!

Now when we talk about XCOM terminology we are all familiar with the absolute basics such as Cover and Flanking. These are all things the game itself will reference, but once you delve in deeper into XCOM combat, you'll need to start understanding concepts that an experienced commander will know. Apologies if you already know most of this stuff, but this guide is meant to cover a wide spectrum of players so please bear with me if I'm going a bit slowly.

• Pod
  I assumed everyone knew what this was, but I actually had a friend who played a decent amount of EW that still didn't know what this was. A Pod is a group of enemies. When you make contact with one enemy in a pod, the entire group activates. For some reason making contact with an enemy while you only have vision on one of them doesn't activate the other members of the pod, I'm pretty sure this is a game play bug but I could be wrong.
  
  
• Fog of War
  This is the grayed out areas of the map, the uncharted territory. Fog from areas that you've already travelled through are safe for the most part, but (This only applies when you do not have concealment) peeking even 1 tile into fog that you have not explored yet while your squad is not prepared is a recipe for squad wiping. The dangers of the fog of war are a thing many new commanders may not be aware of, and I hope to make it clear right now. If all your people aren't ready to react (Everyone does not have both actions ready), do NOT take any moves that will reveal even 1 tile of uncharted fog. The only exceptions are if not doing so will result in a guaranteed squad wipe such as a timed VIP mission.
  
  
• Line of Sight
  All units can see 17 tiles away (Although most weapons can shoot further than 17). This means if you can see the alien, they can see you. For the most part. I believe units on higher ground have slightly more range. I haven't really checked, but I don't see why this mechanic would be different between XCOM 2 and XCOM EW. If you have a phantom ranger spotting for your team and you want to move up to an enemy pod without activating, you can use the Range Indicator to see if your unit is within vision radius. Make sure the enemy doesn’t have that marker on them where you move. If the enemy is on elevated ground, consider staying back about an extra 1 or 2 tiles to be safe. Another tactic is to abuse this by moving important troops behind a wall of full cover without placing them on the ends to prevent them from peeking over. This way, they enemy can’t even shoot at you at all and forces them to move up to a more favorable position next turn. They often dash into bad positions to get you if you do this.

Now that we understand the terminology that's commonly used by plays outside of the game, let’s talk about tactics. Oftentimes players struggling with the game will ask about base management. They may ask what to research and what facility to construct after the GTS. However, I believe that the first thing that players need to improve is combat tactics. We commonly think of the XCOM RNG as ♥♥♥♥♥♥♥♥ when things go wrong at the worst times, but it’s actually the other way around. XCOM RNG cheats in the players favor at lower difficulty levels. Even in commander it will try and make sure you don't miss multiple shots in a row. While this does give newer players a crutch to get through the game, I disagree with this method because it gives players a false sense of understanding. It causes players to think 85% shots are guaranteed hits. It has already been proven in the source code that the Legendary RNG is 100% fair and accurate. A 50% shot is truly a coin flip unlike all other difficulties. Base management should support your combat, but if you find that a majority of your campaigns end in a downward spiral, then the first thing that needs to improve is tactics.

• Moving Through Uncharted Territory
  Timed missions are rough, but we also get a powerful concealment mechanic to make up for this. Use concealment to cover as much fog of war as possible. This is the only time when fog of war can be safely revealed without fear. Make sure to move safely though. Don't actually move into areas you cannot see, because the game won't alert you if a hidden enemy will spot you.
  When out of concealment (Without a phantom), things are exactly like they were in EW. For players who haven't touched the first XCOM installment, this means you should move up to reveal fog when everyone is ready to react. That means everyone needs to have both actions available and ready to reposition. After the scout makes the first blue move and nothing activates, you've made the area safe to move ONLY up to where the scout has moved. All other units are to stay behind that unit. Don't even walk to his side because that will reveal a 1 tile radius of fog that may end up triggering a muton fun lancer pod. I'm sure we all know how much fun that is. Do not think, "What are the chances that we reveal anything here?" In the early game you can predict where the initial 3 pods are, but late game it’s a complete dice roll. Legendary has more enemies on the map. This means you are more likely to activate a pod than in previous difficulties. Respect the alien count and you will be rewarded with living soldiers.
  
  
• Do NOT take every flank
  One of the number 1 mistakes I see people make is running up with a ranger to try and point blank flank a target for the best accuracy possible. As mentioned before, Fog of War is very dangerous. If this isn't the last pod and you can't handle killing the rest of the map, then this is actually a mistake. Unless you know where the rest of the enemies are, you have 2 options for repositioning soldiers:
  In the current area behind the soldier that is furthest out
  Retreat back through area you've already covered
  No matter how appealing that full cover on the side is, do not take it unless you know where the enemies will be.
  
  
• Use Grenades Liberally
  Because you are so restricted with movement when you begin the map, the only way to finish the engagement quickly is to destroy cover and take out all the enemies as quickly as possible. It’s worth it to use a grenade on even just 1 enemy. When you have to take a risk between an 85% shot and a grenade for a kill, just use the grenade. This is because the further you progress in a map, the fewer enemies there are. Once you get to the last pod, you'll be able to move freely to take all those wild flanks without fear of any more enemies popping up.
  
  
• Probability is not BS
  Advent can literally send an infinite number of troops to every mission you go on. They can afford to move their troops recklessly to half cover and keep shooting at one person until they land a hit. XCOM cannot afford even the smallest risks. If you continuously rely on a 90% to kill or be killed, you will be punished approximately 1 out of 10 times you do it. Now the problem is, this is probability so you could be punished 3 times out of the 10 times you do it or you could walk away completely fine. For large sample sizes, a probability will always turn out to be fairly accurate. During the course of an entire XCOM campaign you will take a lot of 90% shots in critical situations, let’s say 50. Then according to probability you're going to lose more or less 5 soldiers in this campaign purely off of the choice to take the 10% risks to miss. Furthermore, during the times those soldiers go down, even more soldiers are put at risk from panic and lowered team firepower. Furthermore, the 5 soldiers you lose are all at random. It could be a useless rookie in the late game, or it could be your highest ranked soldier in the mid game. It’s important that I reiterate that the RNG is fair. It just seems unfair because humans tend to remember moments that affected them the most. So the next time you have to consider between wasting a grenade on a 2 hp commander and taking a 92% shot, remember that it’s not a waste of a grenade.

Now that we've gotten all the tactics stuff out of the way, let’s talk about base management. To be honest, this is actually more flexible than most people make it out to be. As long as you don't make the mistakes mentioned above you can pretty much clear most missions flawlessly with any build as long as you don't do something like take 4 snipers or build 3 power relays in a row. Here's how I like to go for those who like guidelines:

Research

• Start with Mod Weapons
  
• Go Biotech if you want AWC second.
  
• Resistance Comms when available
  
• Radio Relay so you can see continent bonuses and plan out your contact order.
  
• Mag Weapons anytime past this point (When it’s around 40-30 days)
  
• Faceless Autopsy before second retaliation
  
• Trooper Autopsy for scanners before second retaliation
  
• Muton/MEC autopsy when available
  
• Gauss Weapons
  
• Plated Armor

This is a general idea how to research early to mid game. It will all vary depending on how many scientists you get and what you need most at the time. But researching things out of order or at inopportune times won't kill your campaign.

Facilities
I almost always build GTS first; you'll want it up to start training rookies as well as to grab squad size immediately. You can reach sergeant as early as the first retaliation mission.
The next facility you can build before power capacity is reached is the AWC, Proving Grounds, Lab, Resistance Comms, Workshop, or Power Relay.

• Advanced Warfare Center
  AWC is the standard pick for most people, you get halved wound times and all your troops are eligible to start receiving useless abilities LIKE DEEP COVER. (Salty that I never get serial rangers and death from above grenadiers like everyone else) But just the wound time reduction itself is worth having. Even following the general tactics outlined above, you’ll still be put into situations where you can only pick an optimal solution rather than an absolute victory. If you do opt to skip the AWC, the medical assistance HQ perk is still an option when people are out for a few weeks.
  
  
• Laboratory
  Lab Rush is actually not bad at all. The lab is a highly underrated building that I think deserves a lot more praise. Late game its useless, and early game its tough finding time and space to build it. However, getting a lab second and upgrading it fast will allow you to get mag weapons so fast that you'll have it shortly after meeting stun lancers. I often have Mag and Gauss before raiding the Blacksite. Sometimes I even have tier 2 armor on the Blacksite if the appropriate black market merchandise shows up. On my current run, I just came across Andromedons and I'm already rocking plasma pistols. This is the way to go if you get an early engineer and find that getting ready for new enemies like andromedons and fun lancers are the hardest things for you to handle. You'll want resistance comms soon after to keep up in supplies for the things you want to build.
  
  
• Resistance Communications Relay
  Resistance comms are a decent choice for a second building too. If you see some really good continent bonuses nearby (Triple weapon mods, intel boosters, GTS cost reductions), consider getting this. It will also make all your supply needs go away while allowing you to maintain better control over the avatar timer by raiding facilities whenever you want.
  I've never tried the workshop, and it sounds pretty terrible to rush, but maybe it’s actually amazing and no one has discovered its amazingness yet. Let me know in the comments if you've tried this before, and tell me what you thought of it.
  Power relay as a second building serves for the Psi Rush. Research Psi as you finish up the relay, then you have enough power to get psi labs running and start pumping out psi troops. This is kind of a double edged sword because if you send out psi troops a lot, you'll end up taking all the kills that your troops need, but you'll also never need to worry about not having high ranking troops to work with because you'll have 2 powerhouses waiting in the wings. Having early stasis vs. Stun Lancers and Mutons early on is just amazing.

Honestly you can build just about anything other than a blademaster and it'll probably benefit you. But the general rule of thumb is to prioritize Grenadiers and Rangers. I like to have at least 3 grenadiers on my roster if possible. More is better since a grenadier is the least useless squaddie you can have late game. I do recommend having at least 1 gunner grenadier. Chain shot shredder is very important for late game threats. Holo target on big targets like archons is also very valuable.

Now we're going to go in depth on how to handle each mission type. Early game "Easy" missions have only 3 pods on them. On missions with target points or objectives the pods are usually placed in these 3 locations:

• Between the objective and the drop point
  
• At the objective
  
• Behind the objective

Knowing this will give you enough flexibility in your movement to break a few of the rules we discussed before, but don't push it too hard. Later on moderate missions will still hold 3 pods, but each pod will be filled with fun lancers. Then once difficult and very difficult missions appear, you basically assume there's a pod every step you take into fog.

• Guerrilla Ops
  These are the standard missions you'll be facing. Pick whichever dark events you want to stop, but there are a few dark events that will really kill you if you're not prepared, so be on the lookout for those. I particularly don't like the ones that allow more alien forces on the map such as drop ins and hidden enemies. The Alien Cipher one can also be devastating early game. Make sure to use concealment to its fullest and cover as much area as possible before engaging. Also never try sneaking past a pod, it'll take too much time and they usually catch you off guard when you're engaging something further into the map. Just eliminate the first pod you see with speed and efficiency.
  
  
• Retaliation
  This is the mission filled with all the nasty melee attackers. I recommend ignoring the civilians if you feel like you aren't prepared. If you kill all the aliens and let all civilians die you still keep contact with the region and get the faceless corpses for the meme beacons. You'll just lose a little bit of income. Make sure to still rescue civilians as you progress though (Just don't rush to try and keep 6 civs alive), otherwise you'll end up with a faceless right next to your squad.
  
  
• VIP
  VIP missions are the big missions. They are usually high risk high reward. You literally cannot afford to mess up here or it’s basically a squad wipe. 12 turns to run across the map and clear the enemies while dealing with a drop in is brutal. Unlike a Guerrilla mission, if you mess up there's no evacuating at will. Bring your best troops and play as best you can. Consider killing the Dark VIP if short on time. You only lose the intel award and having an extra gun shooting an enemy rather than carrying one may be the difference between getting out or staying forever.
  
  
• Supply Raid
  The supply raid is the easiest of the missions and a personal favorite. The rewards are great and you get the best of XCOM 2 and EW. You'll start out with concealment and you'll have unlimited turns to kill all the aliens on this map. Furthermore you can evac whenever you want. Even if you don't have your best team, all you have to do is slowly inch forward and overwatch camp until you win. Seriously, overwatch is broken on non timed maps. These maps tend to hold tougher enemies, but being a non timed mission more than makes up for a few tougher enemies. The first time you do this will be the toughest because of the large amounts of fun lancers. The first pod is usually 2 fun lancers and an MEC/Viper. If possible I recommend placing all your shooters on high ground and initiating with a grenade to hit all 3 of them for a total of 9 damage. They'll have a combined hp pool of about 26 so expecting a team of 4-5 people to output that damage is tough. But if you have your grenadier do a 3 man grenade, you'll inflict 9 damage total meaning you'll only need to do another 17 damage to the rest of the enemy pod which is fairly reasonable if you have a second grenade to hit multiple targets or a bunch of good shots. I recommend having multiple grenadiers here if possible.

Some Sample Missions
Here are some early game missions where I try to explain my moves in detail. I'm not really experienced with formal recording and I didn't really want to make any mistakes during an Ironman run showing how to play properly so I was a bit nervous and stuttering at some points. Made a few mistakes too, but hopefully it illustrates how to handle every mission you go through from now on.

Finally, we're going to cover enemy types and discuss which ones are the bigger threats. Sometimes you just can't kill them all; this is XCOM where anything can happen. It’s important to adapt to each situation when you can no longer follow the key rules of engagement. This section will help you prioritize which ones to kill and give you a bit of detail about how to handle them. I don't know if I'll cover all of them, but I'll be sure to talk about the ones that give people trouble.

• Trooper
  By themselves they aren't that big of a deal. They can do 3 damage max unless they crit. However, they often appear in groups and with a leader making them deadly if multiple shots do connect. Early on when you have rookies and squaddies, these guys will be the main threat. Try and kill them in groups with grenadier grenades. Guaranteed damage is a nice way to finish them off after a grenade such as combat protocol or stocks. Later, advanced troopers will come with 9 hp, tons of damage and grenades. These guys become huge problems if you don't have Gauss technology by then.
  
  
• Commander
  These guys pose the biggest threats early on with high hp, and good accuracy. They actually have stats very similar to thinmen, except they can also mark you and turn the Troopers into threats too. Early on, you should choose between killing all his buddies or just focusing him down by himself. Don't end a turn near a commander with units grouped up or he'll blow you up with a grenade. Spread everyone out if a commander is alive.
  
  
• Sectoid
  These guys are a relief to see when you have everything under control. They usually end up giving you a free turn since they usually summon zombies or try and panic even when a soldier is flanked. You can basically ignore them for one turn. After that they become a huge threat. They have 10 hp and the same 75 aim and 10 crit that a commander has. Hopefully they die before the zombies actually pose a threat, but if you have no other choice, there's nothing wrong with killing a zombie threatening your position. I like to save flash bangs for when zombies start overwhelming the squad or when they land a mind control. Only bring 2 flash bangs at most though. Anymore and you'll find that you don't have enough grenades.
  
  
• Viper
  These guys will start appearing on the first retaliation. This is also when combat starts getting fun. Sneks will primarily use the grab first. Then after that they choose between Acid and Shooting. They will acid if they can catch at least 2 people. So never ever keep people within a 3 tile radius of each other. This will force them to shoot. While the shot can be lethal its better than 2 people panicking and doing silly things with their explosives. Ideally you actually WANT the viper to grab someone as it’s the least dangerous thing it can do. I've seen venom last for 6 turns and soldiers panic on the last turn before they can evac. At most wait to see if a soldier will be cured by 3 hp before evacing. Soldiers can be panicked for 2 turns and they will not be extractable. If possible, you can move a soldier up to a viper before the end of the turn and let them get binded to hopefully prevent the viper from missing the grab and then critting someone in cover with plasma. A close up ranger or grenades can deal with their annoying dodge habits.
  
  
• MEC
  If you see these in a pod, kill them on sight. They prioritize using their missile attacks on grouped targets and their regular shots hurt a ton. The AOE (Area of Effect) on their missiles is also larger than a grenade. Shredder is a good start as well as combat protocol from a specialist. After you kill one, you can research gremlin 2 and start doing 6 damage per combat protocol. Rangers are also surprisingly good at dealing with low armor targets.
  
  
• FUN LANCERS
  These guys. They are what a majority of players have trouble with. Their seemingly infinite dash range along with their 15% crit chance just makes them absolutely deadly. Flash bangs are not an answer to stun lancers because aim penalties no longer penalize crit chance. On a side note, this does not mean flash bangs increase crit chance, it just means crit chance doesn't go down after an aim penalty due to the new ways the game calculates crit. Besides, as explained above we should always be worried about a 15% chance to crit. About every 6-7 attacks a fun lancer makes is viable to crit so we want to make sure to kill these guys on sight. Their movement range is so huge that if a soldier can see them, the soldier likely cannot outrun them to safety. They get 8 hp and can spawn 2 per pod at a time to maximize fun factor. Having a band of 4 soldiers deal 16 damage in a turn requires perfect execution. Thus it is imperative to get squad size 1 before they become commonplace in all your missions. I often prefer to use grenades to destroy cover, but this is the exception. Use the AOE of the grenades to deal as much damage to the fun lancer pod at once. High damage weapons like snipers and shotguns are golden here. These guys are probably one of the hardest difficulty spikes in the campaign so be ready. They'll show up in large numbers on all missions during mid game including VIP missions just so they can make your day extra fun.
  
  
• Andromedon
  For the most part I stick to early and mid game talk, but the andromedon will break this rule because it’s so deadly. Never give the first form a turn if your soldiers are clumped up. Every attack this thing has will hurt a ton in general. Tons of armor and tons of hp make things even worse. When this thing shows up, make sure to have a really strong gunner available. Preferably with a superior scope or perception pcs equipped to make sure the grenadier doesn't miss the shred. Start by removing its cover and chainshot shred it down. Finally have a blue screen round gunslinger/sniper with lightning hands take down the robot form. Note, you can flash bang it in form 1, but it has 80 aim. This means even in full cover, the disoriented andromedon has a 20% chance to nail a soldier for 11 damage. 1 in 5 chance to die is not something I want to take unless it’s my last choice.

This guide mostly covers the early to mid game since that's usually the hardest part. If you can get past that part, you're definitely good enough to finish up the game without help. At this point, the only thing left to do is go play yourself. If this were an XCOM textbook, the guide would be the explanation on the theory and the videos were the example problems with solutions. Now you need to do the practice problems yourself by turning on legendary Ironman and losing a few campaigns. My goal was to try and get as many people to experience XCOM 2's hardest difficulty. Many people see themselves as a casual gamer, and they may be afraid of trying out a difficulty that feels beyond their grasp. This is completely fine if you don't want to spend the time to get too much into a game, but if you're one of those people that wanted to take the next step into XCOM, I hope this guide helped you take those next few steps to becoming a Legendary Ironman Commander. Good luck and feel free to ask me any questions!