Mage Slayer 5E: DnD Feat Guide

Sometimes that magic wielder just has to die, and at mid to high levels that is a tall order if your party is facing anyone even remotely competent. Also depending on the type of campaign your table is playing, the inevitable betrayal of a double agent wizard in the group can be a serious problem if the rogue in group hasn’t picked up on the subtle hints being dropped throughout the campaign.

The mage slayer feat is a melee combatant’s answer to dealing with spellcasters and the many overpowered

The mage slayer feat from 5E is a strong specialist feat designed to give strong advantages to melee based characters who want extra power when taking on dangerous spellcasters up close in their 5th Edition D&D campaigns.

So does 5E’s mage slayer feat hold up? Does it help to even the field, or does it fall empty on its promises? Read on for an in-depth breakdown to find out.

wizard in sniper rifle crosshairs
Take the shot! For the love of the gods, take the shot!

Breaking Down the Mage Slayer Feat

The first thing we need to look at is the definition of the 5e mage slayer feat directly from the Player’s Handbook.

Mage Slayer Feat, Directly from the Player’s Handbook:


You have practiced techniques useful in melee combat against spellcasters, gaining the following benefits:

  • When a creature within 5 feet of you casts a spell, you can use your reaction to make a melee weapon attack against that creature.
  • When you damage a creature that is concentrating on a spell, that creature has disadvantage on the saving throw it makes to maintain its concentration.
  • You have advantage on saving throws against spells cast by creatures within 5 feet of you.

PHB, P.168


Now that we have the book’s definition of the Mage Slayer feat, let’s break down each benefit and see what this can tell us.

Benefit #1: When a creature within five feet of you casts a spell you can use your reaction to make a melee weapon attack against that caster.

I absolutely love this part of the feat. There aren’t many uses for reaction in 5th Ed D&D, and multiple classes don’t have a common use for a reaction in their class, only actions and bonus actions. This means for some characters this gives reaction a use it doesn’t otherwise have.

The ability for a barbarian, fighter, monk, or other melee class to strike as a caster begins can be straight up deadly at low levels, and at least does enough damage to increase your chances of the party being able to bail you out at middle to high levels.

Considering this is a feat designed for melee characters to close the distance with spellcasters and get down and dirty, it fits in perfectly with the point of this feat, its use in game, and the flavoring of a campaign.

Benefit #2: Creatures concentrating on a spell have disadvantage on saving throws to keep concentration up when you hit them.

Casting classes are built to make saves when it comes to keeping concentration. This makes sense since the save will be attached to their casting stat, and of course they will be trained in saves of that ability score.

So the ability to just straight up get in their face and force disadvantage, giving you a legitimate chance at breaking concentration (though still a challenge at higher levels) is a really good feat attribute. This fits in both thematically and mechanically, and makes a mage slayer character doubly effective for their party.

Benefit #3: You have advantage on saving throws against spells cast from creatures within 5 feet of you.

Mage slayer would be one of the better feats in 5E even with just the first two benefits, but the third really brings home the idea of that martial combat specialist who trained specifically to deal with magic casters. Not only does this feat give you the skills to attack a wizard or sorcerer and interfere with their casting, but you have advantage to protect yourself from their spells.

Note this isn’t just attack spells, it’s advantage on any spell that has a saving throw so this could include spells that control you, banish you, or do things other than direct damage.

Of course, the direct dodge of damage is greatly appreciated, as well.

This is one of those feats where all three benefits work together really well. Both mechanically and thematically.

5E Classes That Should Take the Mage Slayer Feat

The mage slayer feat works well with a variety of builds. There are five classes in particular that this feat meshes with well, and there are arguments that some of the others in the “consider this feat” category could actually be bumped up to this one. If you are the appointed “deal with the robed problem” guy on the team and you’re not a sharpshooting ranger who can hit the target from ridiculously far away, then you should probably look at this feat.

First there are the armored martial fighters who can do very well with this spell: fighter, cleric, paladin. All three of these classes can make the mage slayer feat work. They are armored, have high HP, and are expected to fight and tank. They can tank the magical blasts as they tank their way towards the problem spellcaster.

The monk is another excellent option for picking up the mage slayer feat. Their extra mobility, stunning strike ability, and reliance on mobile movement versus direct confrontation makes them a great choice to go after the spellcasters. Add in excellent Dexterity and Wisdom scores with the benefits of Mage Slayer and they are specially equipped to deal with spellcasters once they can close the distance.

The rogue is another fantastic choice, and the most likely choice to terrify low to mid level spellcasters. The ability to stealth without any sign, and then break out for a devastating sneak attack that is followed up with a refusal to leave the space could run the shiver down the stoutest wizard’s spine as they are face to face with the Shadow Slayer 🙂

Any of these classes are an excellent choice for picking up the mage slayer feat in 5th Edition, and should always look at doing just that.

5th Ed Classes that should always take the Mage Slayer Feat:

  • Cleric
  • Fighter
  • Monk
  • Paladin
  • Rogue

5E Classes That Should Consider Taking the Mage Slayer Feat

The two classes that fall somewhere in the middle are barbarian and druid when it comes to the mage slayer feat. The thing is: these are great classes and the feat can be very effective for them, too.

The main concern is the role that these classes often play in the average adventuring party in D&D. Barbarians often tank, and when facing a challenge usually the tank holds the line while other party members work around that. If the tank is charging to the back…what happens to your squishy characters?

If you have a party heavy with fighters, paladins, clerics, and other high HP, heavy armor melee fighters than go for it. But much of the time the barbarian is crucial to holding the line.

The druid is an interesting one. With wild shape they have the ability to fly, move, and get around the battlefield to approach a guarded back line or even surprise them from above.

On the other hand, druids also often find themselves using wild shape to help tank or using their spells to deal out healing and support in short-handed parties without a bard or other support caster.

This versatility could make a druid a terrifying wizard killer, but it could also make them too integral to group battle plans to break off on their own. Look at the group build before deciding if mage slayer is right for your druid or not.

5th Ed Classes that should consider taking the Mage Slayer Feat:

  • Barbarian
  • Druid
  • Specialty-based builds of melee-based rangers, bards, warlocks, and wizards

5E Classes That Should NEVER Take the Mage Slayer Feat

This is a feat that is based around melee attacks and so it doesn’t make sense for most conventional builds of casting classes, or ranged fighters. Because of this you have most of the casting classes that should never take the mage slayer feat, and then you have rangers.

There are specialty builds with many of these classes that are the exception to the rule, but even in those situations they often require special feats or a focused build. Since that is the case, there might not be room to add this feat. Or there might be a monk, fighter, or rogue who is better built for it.

These are classes that just aren’t a natural fit for mage slayer in most builds and situations.

5th Ed classes that should never take the Mage Slayer Feat:

  • Artificers
  • Bards (exception being melee bards from the School of Valor)
  • Rangers (exception being melee based rangers)
  • Sorcerers
  • Warlocks (exception Pact of the Blade or Hex Blade)
  • Wizards (exception Blade Singer or Battle Mage)

Final Feat Grade for 5E Mage Slayer

Mage Slayer Feat Grade: A

Is the 5E Mage Slayer Feat Worth It?

There aren’t many feats in 5th edition D&D that have received an A grade from me, but mage slayer was an easy A. This is a fantastic feat that fits both mechanically and thematically into DnD and fully justifies the loss of an ability score increase. This feat offers reaction attacks on a spellcaster close up, advantage on dodging or saving from spells, while also getting advantage on breaking concentration.

That’s a lot of benefit in one feat. Considering most spellcasters have low hit points and relatively low AC without using spell boosts, this feat becomes all the more powerful because it allows martial characters to go “whole hog” on the spellcasters being attacked.

This is a relatively versatile feat that works with any of the martial classes and really can change the course of the game. An excellent feat all the way around.

Mage Slayer Feat FAQ

Does the mage slayer feat interrupt a spell?

The mage slayer feat does not interrupt a spell. The only time this occurs is when the spell is already cast and the attack results in a failed concentration check on the part of the caster. This does not include concentration based spells in the process of being cast.

Does mage slayer work on cantrips?

Based on the way the wording is in the book, mage slayer does work on cantrips.

Is mage slayer a good feat?

Mage slayer is an excellent feat, and one of the highest rated in the game for melee classes. This is a feat that isn’t just good for specialists but is a very good feat in general for most combat focused classes.

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