Mage Slayer: Underrated or in Need of a Buff?
Evaluating items in Dota is much tougher, compared to comparing hero stats. With heroes, we can look at their win rates in different brackets, at their popularity, and at least get a general idea of how they fit into the current meta and why. With items, the situation is much harder, but today we will try to use somewhat limited tools at our disposal to figure out whether Mage Slayer is underrated.
End-game inventory
The items we see on this page and their corresponding stats are what players have in their inventory at the end of the game. This is important, as it decreases the win rates of “tempo” items that are purchased in the midgame to gain an advantage, but are later sold.
The effect was most apparent a couple of years ago when Drum of Endurance was a must-have item on any team and pubs followed suit, but it still had a sub-50% win rate, as successful players simply sold them by the end of the game, to free up an item slot.
As such, relying on these statistics blindly is hard. What we can do, however, is compare 
Mage Slayer as the end-game item to similarly priced end game items.
This month, Mage Slayer had a ~56% win rate as a slot in the inventory in the late game. It has a cost of 3250 gold and as such can be considered to be in the same price category as a wide variety of items. We counted twenty one such item, starting with some of the cheapest complex artifacts such as 
Witch Blade, 
Maelstrom and 
Eul's Scepter of Divinity and ending with 
Kaya, 
Sange and 
Yasha derivatives, as well as 
Battle Fury.
Of these, only eight items have a higher win rate as an end game inventory item:
850 gold more expensive and slightly overtuned Sange, Kaya, and Yasha derivatives all get over 58% win rate. Sange and Yasha, the most likely to compete for a slot with Mage Slayer, is at 58% exactly, so the cost-benefit is comparable. Moreover, in some games having both can be worth it.
Specific teamfight-enhancing items, such as
Pipe of Insight and 
Crimson Guard are at ~58% win rate. These are teamfight items and when used correctly in a correct game they can have a massive effect. Pipe alone is potentially 2000 extra HP for your team.
Lotus Orb is still one of the best defensive options with an almost 60% win rate in the end game. It is that good in the later stages of the game. It is also usually built by supports, so if a support has almost 4000 gold to spare, chances are - their team is winning.
Aeon Disk together with 
Solar Crest are the only two items that outperform Mage Slayer, while costing less gold. The former is unsurprisingly OP with a 59.5% win rate, while the latter is ahead of Mage Slayer by 0.10% this month.
Stats-wise, Mage Slayer is seemingly decent. It outperforms having a Battlefury in the late game and is even ahead of 
Diffusal Blade. It is also better than 
Desolator, 
Heaven's Halberd and 
Orchid Malevolence.
Naturally, it is only at its best in very specific games and low popularity indeed often results in a higher win rate, since the item is built only when players know what they are doing and why they need it, as opposed to building default. Yet, it is still proof enough that there are games where Mage Slayer is good and worth considering. We just need to figure out how to identify these games.
Lost in translation
With a name like Mage Slayer one would assume the item is at its best when dealing with mages. Nukers and high burst damage heroes like 
Zeus, 
Queen of Pain, 
Invoker, 
Skywrath Mage etc. are who come to mind when one hears the term “Mage”. While the item is certainly decent against them, we don’t think it is at its best against them.
The problem with Mage Slayer and Mage interaction is that any competent player who knows how to play a nuker type of hero will try not to be in the range of an auto-attack before unloading their arsenal of magics. They want to appear on your radar for a brief window, cast their spells on a priority target very fast and disappear into the shadows, before your team gets to react.
Mage Slayer won’t do anything against them, even if you manage to catch them afterward: the damage is already done and the Mage Slayer debuff at this point is close to worthless.
It doesn’t mean the item is useless, however. Far from it, in fact, especially in the current patch, where we witness a resurgence of heroes like 
Leshrac, 
Bristleback, 
Necrophos, 
Timbersaw and such. Heroes who deal high sustained damage, but need to be at the front of the fight, are usually the ones who will suffer from Mage Slayer the most.
Sure, the magic resistance on Mage Slayer might not be very effective against Bristle or Timber, who are physical and pure damage heroes, but the debuff itself is already worth it. When Bristleback’s Quill Spray starts dealing 350 physical damage instead of 550, or when Timbersaw’s nukes all start dealing less than 150 pure damage, it is pure value, no pun intended.
Against someone like Leshrac, it gets even prettier: under the debuff, even with the level 20 talent, Leshrac deals 155 damage from each pulse, before reductions. A hero with Mage Slayer will be taking roughly 85 damage per second after all reductions, which is quite manageable. More importantly, they will be helping their team and their supports survive.
We think the item was misnamed, resulting in it being underappreciated. “Frontline Hero With High Sustained Damage-Dealing Capabilities Mitigator” is a bit of a mouthful, sure, but it would be a much more accurate description and would probably result in it being more popular and perhaps even more successful.
What do you think of the item now? Did we convince you to at least give Mage Slayer a shot, or do you still think the item needs a couple of buffs? Leave your thoughts in the comment section below.
Good article!
Slight oopsie in this part of the article I think, it reads the former twice: "The former is unsurprisingly OP with a 59.5% win rate, while the former is ahead of Mage Slayer by 0.10% this month."
Thx, fixed!
It doesnt do anything exeptionally good, hence its a garbage item. If u want magic resist, get a hood for 1500 gold less. If u want damage get a diffu wich has an active and manaburn or a deso that lowers armor . Its just not good enough for anything , there are better items for everything it does. Nobody would even notice it being removed from the game
Mage Slayer Ember Spirit!
One of the things I like about the mage slayer is that it has a recipe with an incredible value despite its atrocious build-up. 400 gold is what combines the components, grants an extra 10 agility, 5% magic resistance, and grants the attack modifying passive. A notable hero to take advantage of this in my opinion is Riki. Having both an S&Y and a Mage Slayer in some games can make you a hard-hitting and mobile frontline menace that can freely initiate on almost any hero in the mid-game when you're relatively the strongest.
One thing I wish this article would also discuss: heroes that would ideally pick up this item.
Certain heroes like Ember Spirit, Void Spirit, Puck, Mars, and Medusa all have some means to distribute their attack modifiers to multiple targets (albeit Medusa needs to be level 25 and usually wouldn't want to be caught with a mage slayer at that point). Whereas a pipe aura offers 10% magic damage resistance, imagine hitting 3-5 heroes with sleight of fist and protecting your team from almost a third of the enemy team's spell damage (I know with the pipe it's the active that provides more value, but mage slayer protects against physical and pure damage sources as well provided they're spells).
I think Axe should be one of the main heroes mage slayer is purchased against, as he forces enemies to attack him in order to deal damage.
I agree that on paper Leshrac and Necro, who deal constant or sustained AoE magic damage in team fights are arguably the best targets for a mage slayer. The funny thing about using it on other mid or support nukers is if you jump them as a carry none of them will try to burst you down with spells anyway but instead use escape abilitiesor disables, and that's where the item loses its value.
Which one is worse? This or Yasha and Kaya?
Yasha and kaya is good
Suggestion for the item.
Either make it toggleable like treads
or
the build up should be blade of alacrity/ogre axe/staff of wizadry.
Opens the item to all heroes.
Oooh, I like you ^
The way i see it, mageslayer is like hood with more offensive capabilities. perfect for agi carries bcs they suffer the most from magic damage.
suggestion for the item : change the passive to "when you get hit with spells (not right click) debuffs the caster of the spell for negative x percent of spell damage"
this way, the item functions more like a hood that protects the main hero while providing much better teamfight contribution without having to right click the enemy.
I think it's decent on monkey king
Completely shutdown heroes like BB and Timber, and also hurts Spec to some degree. Axe is already bad, and this item is really a nail in the coffin. Support Hoodwinks have been using this item, but very few supports are able to farm or effectively use the stats from this item.
I remember before 7.07, silver edge used to be able to reduce the damage output of heroes by 50%. Then all of a sudden, that debuff was removed as developers realized that it was too op. Now developers are realizing that heroes like BB which relies so heavily on damage by quil stacks and the fact that silver edge only lasts for 4 secs, while mage slayer can continually keep the debuff on BB, and a sniper can easily man up against BB with that item, it is inevitable that changes will come soon for this situationally broken item.
Illusions should apply the debuff, that would make this item relevent.
It's absolutely inappropriate for the Mage Slayer to be togglable, it is meant to be with the Agility component, bit of magic resist, bit of armor, that's the nature of it, that's how it has to be.
i've been building this whenever i'm against the heroes listed and i built it as a meme item on lycan first item, it's really good :)
1. The components are too expensive to be an item for supports.
2. Not a farming item. Even the AS is meh, to be a 1st item.
3. Does not help you escape ganks compare to shadow blade which is cheaper and more AS.
4. The stats are not that good except (more damage) to Agi Heroes.
5. Does not help you against disables to be a 2nd/3rd item like BKB or Manta.
6. Does not work with your illusions.
7. Enemy spells could kill/disable you before you can apply the debuff to them. It's even more problematic since agi heroes mostly have low HP.
8. The debuff is dispellable.
9. It is a single target defensive debuff.
My Suggestion:
1. Give it an Active. A Chain Lightning that applies its debuff and deals damage to illusions.
2. Replace recipe with Morbid Mask (lifesteal) to make it somewhat worth it for a late-game item choice for cores.
It needs an active to make it worth buying and 750 gold cheaper.
Mage Slayer should get a similar treatment like Meteor Hammer. The current buildup is absolutely weird. I could see some agility heroes use this against certain matchups, BUT 3250 gold for that kind of stats/effect is super crap.
Diffusal cost 3150 can dish out a good amount of damage while burning mana. Hood Defiance costs over 50% less than Mage Slayer and provides much value.
u/Firewall above already stated the problems. This item either gets an ultra rework or is completely removed from the game.
If Mage Slayer build toward carry/hitter hero, then it should be having Hood + Falcon Blade + X + Recipe component. Falcon Blade makes much more sense rather than clunky Blade Alacrity + Claymore.
Mage Slayer is way better than I thought. I assumed it was garbage because I tried to buy it against Zeus (where it isn't good).
the thing with this item is it falls short compared to other indirect alternatives. generally the offlaner is the preference to carry this with a weird recipe like that.
the debuff is very enticing, but thats it. lackluster damage which most offlanes today doesnt even need, it has no more upgrades, so it gets stuck in your inventory as kind of a one dimensional item, it doesnt help you get your own power spike because it debuffs an enemy, and lets not forget you have to actually touch the enemy in order for it to get applied, which is a big deal because most offlaners will be melee, some will be buying blink daggers to jump on somebody that doesnt need mage slaying. so compared to buying a hood of defiance which gives you resistance plus hp regen which can be further upgraded for a team-wide magic resistance pipe or further boost it into shroud, the mage slayer simply becomes a shadow of an item.
There's too much problematic with stats and gold for Mage Slayer. I think Icefrog can make the item "targetable" to debuff someone while remove the passive to make the item more playable. Or maybe make it 'Shareable' so Carry can give it to support when they have no slot anymore.
The item should have an active similar to Medallion - allowing you to buff your carries or debuff your opponents. extra magic damage output / reduced magical damage received. and vice versa. receipe in general needs a rework anyway - but at least as an active it's viable.
buy yeah, everything everyone said - it's garbage cuz they're items that do the job it's trying to do better.
Good article! :)