Even though CM is the cliché sacrificial support in most Dota memes, she is actually a rather greedy position 5 hero. She is decent at zoning and babysitting mainly thanks to Nova, but she is slow and with bad stats which makes her vulnerable in some lanes. Yet, she can easily get some farm in the jungle and she scales very well with items into the later stages of the game.

Her signature skill is her global mana sustain aura (the free Clarity potion), but her team fight potential from Freezing Field should not be underestimated. In a good game, CM is one of the few supports with whom it’s possible to get a rampage, which makes her fun to play.

CM shines because of her global presence with her passive and her versatility in the laning stage. She is a decent babysitter, could farm the jungle (or create stacks), and with Boots and a good partner, she can rotate for kills in other lanes. This means that with good game sense a CM player can adapt and make the best out of different situations.

It's a good idea to draft CM with heroes with good kill potential in the lanes - Nova and Frostbite provide good damage and lockdown, so if your allies provide additional damage you can easily get kills early. Moreover, drafting her with cores who are self-sufficient in lane will give her the free time needed to get a bit of farm in the jungle or rotate to other lanes in the later laning stage.

CM has great potential to win team fights with her ult, but this is hard to pull off because it's a channeling ability that requires great positioning. Naturally, games where the enemy team doesn't have the needed tools to easily cancel Freezing Field or kill CM, will allow her to have a higher impact in fights.

CM is mostly played as a pos. 5, or rarely as a pos. 4 as she’s too immobile to gank consistently.

CM is an interesting lane support:

• on one hand, she provides great harass with her Nova spam and great kill potential with the lockdown from Frostbite and the slow from Nova if her lane partenr(s) have damage
  
• on the other, she is extremely slow and squishy, which means fast and aggressive lane opponents can exploit this to repeatedly kill her

Because of this, great positioning in the lane is vital. If she has trouble staying in the lane without dying, she has the option to start her rotations: to farm and stack the jungle, to control the runes and most importantly - if possible to gank the other lanes.

In the ideal situation, CM wants to secure the lane for her core in the first half of the laning stage and to start rotating in the second half, when she has Boots and more levels in her spells.

Good friends to have are:

Strong Against:

Weak Against:

Nova range:

CM is quite flexible with her skill builds. The usual idea is to have a high level of Arcane Aura to help your whole team. You also need 1 value point in Frostbite to farm creeps and control heroes in ganks. After that, whether you max your Frostbite or Nova depends on the situation: Nova is better at anti-pushing and cluttered team-fights or vs illusions and small units, while Frostbite is better for ganks with its longer single target disable, especially if you right-click cores who need to stick to their target for as long as possible.

Taking ult at level 6 is optional for any build as the enemy simply might have heroes to prevent you from using it.

On lvl1 you can take either Nova or Frostbite: Nova is better when you are facing dual or trilanes, as it results in much more damage per mana spent. Frostbite, on the other hand, is better versus single opponents or if you want to start farming the jungle as soon as possible.

Due to her many flaws (incredibly squishy, low mobility, channeling ult) CM really only goes for one type of a build (mobility + survivability), but it is versatile enough to allow you to participate in fights, pushes or ganks. Any items in the mid-late game can be replaced with situational items.

Survivability: CM is a very squishy hero, Glimmer/Force might not be enough, so getting the right choice of other survivability items is what you might need if you want to be useful in team fights with your ult. Cost efficient stat items like Bracers, Wand, Drums and Spirit Vessel are the usual choice.

Support items: If its nearly impossible to use your ultimate efficiently, you can focus more on the traditional defensive support items to keep your cores safe (Glimmer, Solar, Force, Lotus). Additionally, these items can allow your teammates to chip away at objectives more safely, while you wait in the backlines for the enemies to go on that core so you can counter-initiate.

Luxury: Usually CM won’t have enough resources to get luxury items, but if the game goes really late, you can consider most of the usual late game INT items that have good synergy with Blink and make you tankier – Hex, Shiva, etc.

• Stacking easy + hard camp next to the lane: this helps with your pulls as it means the creep wave will always get killed so enemy offlaner gets no exp.
  
  
• Stacking hard + medium next to the mid lane: this helps with greedy mid laners who can farm stacks early like Alche/TA/SF.
  
  
• Stacking Ancients + nearest camp: hard or medium both can work, depends on how many stacks there are. Sometimes it might not be possible to stack both at the same time if there’s too many. This helps carries who like to farm them in the mid game, also Ancients provide a huge amount of exp, so whatever time you spent stacking that lost you exp will be returned to you if you are there when your core takes it.
  

Alternatively, if you have nothing better to do and your cores don’t need these camps nor do you need your ultimate, CM can stack 2 camps and then take them both down at the same time with her ult. This is quite a huge exp/gold boost, but leaves you vulnerable if a team fight starts.

As already mentioned, your 2^nd ability does 100 damage for 10 seconds to any neutral creep, meaning you can go into the hard camps and freeze a big creep and leave the small ones. It is usually best to stack first then as the creeps reach the max aggro time and are about to run back you should freeze the big creep and hit it a couple of times. The reason for this is that some camps will have magical resistance auras and some big creeps have more than 1000 HP. Moreover, by doing this you don’t “block” the camp by leaving only one/two small creeps, you leave more than a full camp for your cores.

If you’re not close to the stack timing and you want to farm, it is not a bad idea to kill the small creep, so that a new camp spawns on the minute mark.

Zoning out will be too dangerous so don't attempt it too much, especially when your opponents have Boots and some levels. If you overextend your opponents could chase you down. One or two deaths could easily cost you the lanes - if your opponents have Boots when you don't, you'll have to hug the tower.

When it comes to harassing - Nova is great if you manage to land it on more than 1 hero as it deals significant damage and the slow will let you right-click a few times. Frostbite could also be used on a single hero in combination with attacks. Don't enter into right-click wars, however. Your attack damage is very low, your armor is low and you are very slow, so you will get the bad end of the exchange.

Your spells are great for harassing and using them as often as possible is usually the right choice - you can try to sustain your mana with one or two Clarities and the mana regen from your aura.

CM has no survival potential whatsoever. If the enemy reaches you then 9/10 times you’re dead, so make sure before doing something that you consider what spells the enemy has so you don’t end up killing yourself for trying to harass/zone. Positioning is incredibly key for CM even in the early game.

When it comes to kill potential CM by herself doesn’t have a lot, but combined with a 2^nd support (roamer) she can do a lot. Most roamers have very strong stuns and damage but usually they’re low range so it’s hard to get them off (SK, night, clock) meaning CM with her root can set them up and using her slow they can chase the opponent afterward. It is also completely fine to use the slow first as the extended range could allow you to initate from very far away. When going for rotations you have to make sure that your core knows that you’re doing this, as CM’s right-click damage is nonexistent so 2 supports might not always be enough to get a kill, and especially since you do want your cores to actually land the killing blow so they get the gold/exp lead.

Close range initiations: CM Frostibe> teammates follow-up> CM Nova to chase

Long range initiations: CM Nova > teammates follow-up > Frostbite to chain-stun

The most important timings for you are the stack timings. Otherwise, if you want to rotate – stick to your pos. 4 roaming supp. You are already strong when you have a point in Nova and Frostbite, so you shouldn’t wait for a specific skill timing. That being said, lvl6 is a great timing to kill an enemy core if you have teammates with strong disables.

CM’s first ability is a powerful setup, meaning she’s really good at taking skirmishes at the rune. She starts off by going to the offlane with her roamer ES and offlane DS. They don’t end up finding a kill but they at least manage to secure a rune for their team, since the enemy spotted them they end up taking one of their team’s runes as well, so overall an even trade.

After helping her team grab the rune, and knowing that the enemy has an offlane bat who is likely to snatch the creep wave she immediately teleports to the shrine to catch him. Bat ends up running away with a small amount of HP, but at least she prevented him from completely owning the lane.

She tries to do some harassing but once bat was level 3 she stops and goes to do some pulls instead, as she knows she could easily die if the Bat gets enough Sticky Napalm stacks onto her.

Once it’s night time and she has a couple of levels she can now start roaming around the map with her Earth Spirit. She ends up going to the mid lane and doing exactly that. Even though her ES died, they still managed to get 2 kills onto the enemy mid and roamer.

Once ES is alive they smoke up and head to the safe lane, where they’ll attempt to kill the enemy Bat, though they were unlucky as the Bat spots them. So, they return to the mid lane and get another kill on the enemy mid SF and roamer tusk. ES dies for it again, but of course, it is worth it. She proceeds to ward up on the mid lane HG to prevent enemy rotations.

It’s around 7 minutes into the game now, they already lost the offlane t1 tower and she knows that the enemy’s next move will be rotating to take their safe lane tower. Knowing that and that the enemy is stronger she instead stays a bit in the jungle getting her levels and items, and only counter-ganks till the mid game. Once her cores get their items the midgame starts and they can now do team related moves.

Glimmer Cape: this timing allows you now to get off a very safe ultimate or simply save a teammate. When you get this item it is always nice to try for a smoke play and use your ult to win a fight.

Blink + BKB: This now allows you to jump into a team fight and pop your ultimate, meaning less thinking about positioning - more team fight presence.

None. You’re basically a snail made of paper if you don’t have items and you are in no way a flash farmer. If you are truly behind, your best bet is to play the role of the sacrificial position 6 support and hope your teammates manage to win you the game – stick to your team to protect them, face-tank smoke ganks to let your cores escape if needed, etc.

You have 3 jobs when it comes to team fighting: spamming your 1^st and 2^nd, getting a good ult off and simply using your items to save heroes.

• Nova + Frostbite spam:
  

Your job is to simply throw your nova onto as many targets as possible, Frostbite an important target without potentially dying, or if you can’t get to that target then simply the nearest target is good enough. After that wait out your cooldowns and do it again, going in and out of fight every time your 1^st and 2^nd ability is off cooldown.

• Ultimate:
  

Wait for the right target and timing, don’t rush it. It is much better to simply spam your 1^st and 2^nd ability than to take a risky ultimate that could end up killing you. Wait out important enemy skills that can interrupt your ult before you go in. For example, if there is an enemy ES without Blink, once he uses Fissure this is your cue to go in and cast Freezing Field.

It is also completely fine to go for a single man ult if it means killing their most important hero.

• Items to save teammates:
  

If you’ve already built Glimmer/Force and other items that save your teammates, you should use them when needed while you are in your “Nova + Frostbite spam” phase instead of saving them for your ult.

• Example:
  

PPD plays a position 6 CM and the team fight for his team starts relatively badly. The enemy team gets the initiation, but his good positioning allows him to survive for a long time. As soon as Omnislash ends he is able to cast all of his spells: they stun lock the enemy Jugg and they finish him off with the help of Freezing Field.

• 5-man pushing:
  

When it comes to 5-man pushing you’re always going to be sitting in the backlines. CM has no right click DPS and most heroes want to pick you off before a team fight starts as you’re super squishy. You should sit behind trees somewhere waiting to counter initiate with your Nova/Frostbite or to use your Glimmer/Force to get your core to safety.

• Split-Pushing:
  

 CM can’t split-push efficiently by herself. She’s ridiculously squishy & slow, meaning almost any hero that finds her would end up killing her.

This can be used as a bait, though. If your teammates are waiting behind you they can counter gank - as mentioned most pub players who see a lone CM will instantly run there and try to get the free kill (we say pub players, because in pro games a lone CM is extremely suspicious).

Similarly, putting yourself in a dangerous position could actually draw the attention of the enemy team (who are hungry for the free kill). If you force a TP, for example, this might give an opening to your teammates to make a move on the other side of the map – to take Rosh or a tower. Don’t forget to type “space created”.

CM’s midgame is mostly about warding and ganking, so if you can’t simply group up for a team fight to start taking towers, it is completely fine for you to be running around a teammate to get kills with your ultimate whenever it’s off cooldown.

While the standard support rules for warding/dewarding apply to her, something that should be noted is that her 1^st ability can be used as a scouting mechanism,

As it applies a huge area of vision at the point of cast (900 units), this works really well for scouting uphill when trying to gank, behind cliffs or jungle camps and not to mention for Roshans as it’ll provide the vision for 6 seconds. The vision is centered at the cast point of the ability, meaning that if it clips the Rosh pit, if it was cast outside the pit it won’t reveal inside – you need to click inside the pit to gain vision.