Sentry Wards
Stats:
HP: 200
Armor: 0 (Medium)
Vision day/night: 200/200
True sight: 1100
Cost: 200 gold (2 charges)
Duration: 6 min
Shop cooldown: None
Short about True Sight: True Sight makes all invisible units in the true sight AOE appear visible, and makes them fully targetable. If the carrier of True Sight dies (Sentry Ward, Necronomicon Warrior 3) or the invisible unit leaves the AOE, vision is immediately lost. That means all projectiles (except a few triggered ones) following the invisible unit will miss, even if the unit returns to the True Sight AOE before the projectile reaches it. Most triggered stuns cannot target invisible units, though some spells will still apply damage (Elune's Arrow). True Sight applies to the entire AOE and is not limited by objects, though something must have vision for the invisible to be revealed. This means a Sentry Ward placed on the ground floor (in the river) can look up on the 2nd floor (ledge).
Why should I use it?
-To counter enemy warding.
-To counter certain heros.
-To prevent creeps from spawning.
-To scout for runes.
Using Sentry Wards.
Sentry wards have 1100 range truesight, and 200 range vision, so as scouts they are poor. However, they have no buying cooldown, so you can acquire as many as you can afford. Earlygame, before warding wars begin, they serve only as hero counters and anti-anti-jungling, and as an alternative to Observers as spawn blocking.
Anti-anti-jungling and creep pulling.
Mirana blocks the bottom Sentinel camp with an Observer, to prevent creep pulling. However, Rooftrellen already placed an Eye inside the camp, and Sentinel is able to destroy the ward quickly.
If your team has a bred jungler like Terrorblade, the enemy team might block both the pullable camp, and the small camp. If you krow your opponents are doing this, bring a pack of Sentries along from start. It will give your jungler a slower start (alternatively another hero can buy them), but will also counter the first step in the enemy strategy. Having Rooftrellen place an Eye is also a possibility, as this will not block the camp.
Note that if you pay every camp a visit you remove the green dot that indicate neutrals are present. This will allow you to know if any other camps are blocked, as a blocked camp will not show a green dot. Spawn time is 2:30 in -ap, 4:00 in -rd (and other drafts), and 2:00 in other modes.
Top camp looks like this.
Jakiro placed a Sentry to the left of the camp and attacks the Sentry blocking the camp.
When destroying blocking wards, be sure not to block the camp with your own Sentry. While a Sentry can do the job, often Observers are used to provide vision and perhaps placed where they allow a gank rather than block the camp, like in spot 9. Judging whether to use a Sentry or Observer depends on the enemy lineup. If you want to block two camps to deny jungling, using Sentries will be enough. If you only want to block creep pulling and use the other on a rune spot, Observers are best.
Hero counter wards.
Few heroes need Sentry Wards to be countered from start, but nevertheless oppose an immense danger when not countered.
Broodmother is not that dangerous for the first few levels, but a Sentry Ward from level 1 will give most laners superiority. Failing to counter a solo Broodmother can be fatal very early in the game, especially for soloers with no stun or escape. Whether Broodmother herself should bring Sentry Wards depends on the expected opposition. If it's a double lane that will kill her, invisible or not, the 200 gold will likely be wasted.
Tinker has the upper hand here with two Sentries in mid lane, and is able to stop Broodmother from doing anything.
Broodmother gets her own wards and takes out the enemy Sentries in a few seconds, turning the lane around again and getting first blood on Tinker. Note that Tinker used both wards from start, while Broodmother took out both with only one ward, and still has one in case Tinker tries to place Sentries again.
Weaver will be easier to take on with Sentry Wards. His movespeed and contact damage cannot be avoided with truesight alone, but he'll be much easier to gank with no option to avoid targetable spells with Sukuchi.
Also noteworthy is Watchers with Dark Seer's Ion Shell on. They have 522 movespeed, are easily replaceable, and Ion Shell is rather cheap. If not immediately disposed of, they can do significant damage, and since the bounty for killing them is around 12 gold, they're not worth spending AOE nukes on (read: get Sentries).
Nerubian Assassin requires no truesight until he's level 6, and even then it's not necesarily a good option. Vendetta has a long cooldown and he can kill with supporting heroes without using it. Moreover, placing Sentry Wards in several places in all three lanes is very expensive in the long run. If both towers are up in mid lane, continously keeping one Sentry Ward up may prove beneficial. Later when Vendetta gets a lower cooldown it's near impossible to ward oneself out of harm, and wards should be spend when fight is expected or when attempting to gank Nerubian Assassin. Note that truesight will not negate the backstab damage. Also heroes other than warders might want to keep Sentry Wards for sudden skirmishes in mid and lategame.
Sentinel is pushing and places a Sentry outside Scourge base. Lich has low survivability, and must survive to cast his ultimate in order to win the fight. NA could kill Lich solo if it wasn't for the Sentry.
Mirana is tackled the same way Nerubian Assassin is. Most often Mirana gets Moonlight Shadow at level 10, but one might surprise you and get it at level 6. Ward only before and during fights, or skirmishes where she uses it for her and her allies to escape. Moonlight Shadow is most often used to escape, but if the enemy knows you're not in posession of any truesight (if you carry none and they warded with Sentries), it can easily be used for initiation.
Rooftrellen is pain in the ass. He can do solo, be average support, and let allies escape easily if you're unprepared. He's not much of a threat in a lane, and he's not particularly dangerous under normal circumstances, but he's hard to gank with wards on his own, invisibility, and high survivability, and if he farms intensely he can be a menace in lategame. Always bring wards if you decide he's worth ganking. His Eyes of the Forest (covered later in the guide) have truesight, so placing wards before initiating can be a big mistake, as he can destroy them before going invisible. Also, while the invisibility doesn't work when he's not near trees, it will grant him a second to move toward trees and recast Nature's Guise with it's 3 second cooldown.
Gondar depends on the player's skill, playstyle, and the lane. If Sentries are needed, have them brought later. Gondar himself is weak and Windwalk has a long fade time and supplies no movespeed, so he's much easier to overcome than a Weaver, however, his burst damage is high and with a strong ally he can stomp a lane that has no truesight.
Rikimaru requires Necronomicon 3 and Sentries as backup.
Clinkz is ridiculously weak, but fast and hard to kill with Sentries alone. However, to be of any use he has to reveal himself and risk getting killed. It's my opinion that Scrolls counter Clinkz better than anything when he backdoors and Guinsoo in direct engagement.
Invoker is slow and has a long cooldown on Ghost Walk. Also the aura from Ghost Walk reveals him, and when it's not fully skilled he'll be quite slow even with three Wex. Use Sentries when he tries to escape from a fight or a gank. Note that Invoke has a significant cooldown early in the game, and if he has Ghost Walk prepared he'll lose efficiency by not having more useful skills. So if he escapes from a fight, it only means he didn't use enough spells.
Phantom Lancer requires stacks of Sentry Wards. In the current stable map there's many illusions you need to see through, and in the newest map the remake of Spirit Lance makes him super confusing to fight. Search for the transparent one when he escapes and use an excess of wards to keep chasing him. His spell resistence makes him hard to nuke to death so a chase can be long and ward consuming. Supply Sentries with Necronomicon 3 if he's an escape artist.
Goblin Techies is, even with poor farming and leveling, one of the most annoying heroes in the game. Use Sentries where you're afraid of getting killed and before engaging in a fight. There are always mines somewhere. If you don't see them, it only means they're elsewhere. Supplying with Necronomicon 3 is recommended and gets more beneficial as the game drags on. When you ward offensively before pushing down a tower, drop a Sentry Ward along with the Observer, but remember that Observers have longer sight range than Sentries have truesight range. Remote Mines can serve as wards, which will be covered later.
Rexxar doesn't require Sentries specifically. If you think you're being followed, for instance, if you go to the forest from your lane or after a clash with the enemy, go to a place where a Sentry is placed and try to kill the Hawk.
Ward war.
This is where warders (nice word for ward slave or bitch) shine. Control of the rune spots, avoiding ganks, and creating map control is what warding is all about. Control means the enemy doesn't have vision. To prevent this vision, Sentry Wards are applied together with Observer Wards to identify enemy wards and destroy them or abuse them. First example is the top rune spot. There are several positions for an Observer Ward, on the shores beside the river and on the ledges right and left. These positions give the best vision of the river and rune spot and are the most common. The solution for removing enemy wards is to place the Sentry where the True Sight can reach all Observer spots, which is in mid river. One ward there will reveal all Observers nearby, as long as you have vision. The easiest way to gain vision is to place an Observer on a ward spot, or bring a Flying Courior to give you vision.
The top rune spot has some trickery to it. There are four floors, the river is ground, the shores below the rune is 1st (spot 1), the ledge to the right and above are 2nd, and the ledge to the left is 3rd (spot 7). While the cliff to the right is used most, placing an Observer there will not give vision of an observer on the high cliff to the left without the use of a flying courior. By using spot 7, you may be able to keep your Observers intact and only have to replace your Sentries when they are destroyed.
The warders on each team, Lich and Puck, are both trying to ward top rune spot here. Puck already has wards up and Lich just placed a Sentry with Flying Courier. Note how Puck's Observer in the lower spot on the ledge to the right, with poorest vision (compared to the other spot on same cliff), likely put there in ignorance. Lich's Observer is on the high spot 7, and even if Puck destroys Lich's Sentry, he will be unable to see the Observer unless he gains vision of the top of the cliff.
Lich attacks an enemy ward. Note that enemies have full vision of him. The ward has 200 HP and most heroes early will kill it with three to five hits. Attacking uphill has 25% chance to miss, so taking out a ward can take up a lot of time depending on luck, and is not without danger.
The bottom rune spot should have the Sentry placed on the ledge to the left (spot 2) or just on top of the rune. Like top spot, vision can be gained from many directions, and it's possible to use a faraway one and keep vision on the rune without the Sentry revealing it. As for both rune spots, putting the Sentry directly on top of the rune allows you to see the rune even if your Observers run out of time. It's not a very good solution, but it's better than nothing. Similarly, if you place it on the enemy ward, you can destroy that without using an Observer or Flying Courior.
Lich just placed a Sentry in mid river in the bottom rune spot, already having an Observer on the cliff to the left. This reveals and enemy Observer on the cliff to the right. Had the enemy ward been placed in spot 11, the Sentry would not have revealed it.
NA and Krobelus place a Sentry and destroy the enemy Sentry at bottom rune spot. They don't have an Observer, so they do the following.
This is only possible at the bottom rune spot. NA stands on a cliff, providing vision of the cliff with the Observer, while Krobelus destroys it. If the ward was placed on the opposite cliff, this would be impossible with most heroes at night.
Skills, Items, and Roshan
Just below Roshan, at the entrance, and to the right of the entrance, there are invisible doodads called sight blockers. As the name suggests, they mess with what is normally line of sight. This is an Observer placed on the cliff to the right of the entrance.
It's able to do absolutely nothing. Sentry True Sight works, but all normal sight is blocked, with a few exceptions. Inside Roshan's lair there is full vision, however, a ward placed there will perish immediately. This is a balance issue to make it harder to control Roshan and intercept when the other team engages him.
In a recent version, Rexxar's Wild Axes would destroy doodads, including sight blockers, and a single cast in that area would making warding a lot easier. But when it was recoded not to destroy Sprout, the ability to kill various doodads was also removed. However, other methods still work when it comes to vision of that area.
Except for placing a summoned unit at the entrance, the following skills help scouting Roshan: Techies' Mines, Stasis Trap, and Remote Mines, Rooftrellen's Eyes of the Forest, Lanaya's Psionic Trap, Weaver's Watchers, and Broodmother's Web. Mines have low visibility (64) and Stasis Trap less duration and vision (600) than Remote Mines (900), and since Roshan is rarely killed before Techies reach level 6, only Remote Mines is recommended here.
As seen, Psionic Trap, Remote Mine, and Web provide full vision of Roshan's lair, while showing nothing outside the area.
Using Eyes of the Forest is different, and in a sense much better. The skills is based on Night Elf's Huntress's Sentinel, which sends an owl to scout and provide true sight in a tree. The way it's coded is very unlike the units with vision (wards), as their sight is not blocked by obstackles like trees, and more importantly, sight blockers. They're visible, however, so use a Flying Courier to provide vision of the tree, and place the Eye. It has 2000 casting range, and placing it in trees not visible from the outside will make it near undetectable. The Eye has 690 range in level 4.
To sum up,
Psionic Trap has 400 vision, long casting range, unlimited duration, and is best placed for scouting in Roshan's lair and at rune spots (on top of the rune). The limited vision makes it less attractive as a ward substitute, but the great range, low cooldown, and manacost make it very useful for scouting fast.
Web has 550 vision, somewhat long cooldown, and only 8 can be placed at level 4. When more are placed, the oldest is removed, making it slightly less useful for keeping a constant eye on Roshan. It will allow Brood to stay invisible and steal the kill or Aegis, however, a Sentry will prevent that and the enemy will be able to see the Web and know you have vision. Since the vision is rather limited, place it at narrow key spots all over the map. It will allow you to turn invisible fast, plus the movespeed bonus lets you run away before they can set up Sentries. Another techique is to place it all alone mid lane, giving Broodmother immense power in that area. Web is probably most annoying to the enemy because it cannot be killed in any way.
Remote Mines have 900 vision, low cooldown, and high manacost. With a timed life of 6 minutes and the less vision than Observers (1600), but no shop cooldown, they can work effectively as ward. Do note that they can't block neutral camps, but since they can deal damage to either kill steal or kill the hero, they are useful in neutral camps.
Eyes of the Forest have 690 range, long cooldown, truesight, and require a tree, preferably one that cannot be seen (either behind other trees or on cliffs). They don't block neutral camps. Level 1 can give vision of top rune spot and level 4 of bottom and they are destroyed with a Tango. Eyes are weak wards, so use them as counter wards and place them at small spots where you know the enemy will be gankable, like in his neutral camps. At level 4 the cooldown is 75 seconds, so set them in trees at common ward spots when you have your warder along to kill the enemy wards (Rooftrellen can't because he's melee). Eyes placed in neutral camps have synergy with long range heroes like Zeus, Spectre, and Furion. Furion at level 11, when chosing his moment correctly, can do high damage with Wrath, possibly lethal, and additionally frag neutral units in the camp to deny the enemy experience and gold. Eyes are best against lineups who have nothing but Tangoes to destroy them.
Watchers have 1900/1800 range, low cooldown, low manacost, high movespeed, and limit on total amount. This is probably the most adaptable map control skill, with ridiculous vision in level 4. They can't block neutral camps, but they can make a round to all creep spawns in a short time when put on patrol, and can see Roshan and explore the area around as well. They're best used with shared control and some or all always on patrol in various parts of the map. They die from a single hit though, and Radience will eat them, however, they're easy to replace. Never let them stay on one position like a rune spot, make them use their 522 movespeed and high vision with a short or long patrol order. When a tower goes down, feel free to change the route. Also, always optimize. If one lane is getting ganked repeatedly, focus that area. When the enemy gets Radience or starts taking out Watchers in some other way, set the skill to auto cast to keep replenishing (no new Watchers will be summoned when max limit is reached). Since Weaver should not be warder, let the support heroes set the patrol routes, and remember to micro them when needed to give vision before a battle or a gank. Watchers have the Ghost ability and CANNOT block. Here's an example of Watcher routes. By no means the best or only, just an example. When setting the patrol, select Patrol, hold shift, and click the points in the desired order.
Revenents have 1600/800, low cooldown, low manacost, are flying, and can attack. The ability to attack makes them useless when put on patrol, because they'll attack enemies and get killed. The upside is that they can hover over trees at various spots and are unaffected by sight blockers
Greater Hawk from Call of the Wild has 1600/1200 range, slow movespeed (280), invisibility, low HP, and is flying. It will be killed by one hit from Radience, moves so slow it can't scout a large area, but provides vision from above that makes juking impossible near trees. Since it's one of Rexxar's main assets, dedicating it to watching Roshan or runes permanently is a waste. Note that it has highest priority from towers, so leave it outside it's range when tower diving, preferably on the offensive side to be aware of incoming heroes.
Anti-warding
This is when it get's expensive and fruitless to ward. The best anti-warding measure in the game is Necronomicon 3. Since warding can be game breaking and lots of fights break out while attacking or protecting wards, removing wards without risking heroes is a strong tactic. The level 3 summons have 425 movespeed, the melee has truesight, and the ranged sufficient DPS to quickly kill wards. They cannot see uphill, but with a Flying Courier tagging along they can dispose of all wards. They're also useful for moving quickly into enemy ground and remove Sentries prior to an engagement.
Akasha, Rexxar, and Puck are probably the strongest anti-warders with Necronomicon 3. Akasha and Puck can move up to the ward spots themselves and dispose of wards, and have more than decent escape measures. Also, by the time they have the item, they have sufficient DPS to dispose of the wards so fast they are in no immediate danger. Rexxar is one of the only melee heroes who can kill wards on ledges, and even without putting himself in danger. With Necronomicon 3 summons and his own summons, he can get vision of ledges and dispose of wards.
Since Observers have 6 minute duration and 6 minute shop cooldown, losing them like this can quickly kill the supply. If both teams use this tactic, they have to rely on something other than wards for controlling the game (a very chaotic state), or use alternative ward spots. An alternative is anything that is hard to discover and has less use than optimal spots. If the enemy doesn't know where to search, it will make them uneasy or think you have given up on warding, something you must never do. As warder, you're Rick Astley, and you're never gonna give up your team.