One DnD Mage Slayer Feat Guide

Spellcasters are feared, and with good reason. The power of magic is unrivaled in most areas of 5th Edition D&D, and for low-level and mid-level adventuring parties that have run across that Big Bad Guy who had high level spells, the pain is real. So is the fear. For martial characters who have been pushed around one too many times by the enemy spellcasters, there’s the popular Mage Slayer Feat making a return.

The One DnD Mage Slayer Feat allows a player to increase their Strength or Dexterity by 1, impose disadvantage on a creature that concentrating when you damage it, and Guarded Mind allows you to turn one INT/WIS/CHR saving throw fail into a success per Long Rest.

Is this enough to help balance out the scales against magic users? Does this feat hold up in actual gameplay?

tiefling fire mage
Hi, our Fighter and Barbarian would like to make a close up introduction to deal with you…

Let’s dive in and really dig into what this feat has to offer!

Mage Slayer Feat DnD One Review

The best way to break down a feat is to check out the exact wording.

From Unearthed Arcana:

4th-Level Feat

Prerequisite: Proficiency with Any Martial Weapon

You have practiced techniques useful in battling magic-users, gaining the following benefits:

Ability Score Increase. Increase your Strength or Dexterity score by 1, to a maximum of 20.

Concentration Breaker. When you damage a creature that is concentrating, it has Disadvantage on the Saving Throw it makes to maintain Concentration.

Guarded Mind. If you fail an Intelligence, Wisdom, or a Charisma Saving Throw, you can cause yourself to succeed instead. Once you use this benefit, you can’t use it again until you finish a Long Rest.

Unearthed Arcana, Expert Classes, 2022

Let’s break down each of these benefits one by one to see how the new Mage Slayer Feat really stacks up.

Benefit #1: You increase your Strength or Dexterity score by 1, up to a maximum of 20.

A half-feat here makes sense. This feat is flavor-texted as being training, so why would you go through training without improving your base combat stat? A simple ability score improvement, but better than not getting one at all.

Benefit #2: When you inflict damage on a creature that is concentrating, it has disadvantage on its saving throw to maintain concentration.

This is an excellent benefit. Concentration spells can be dangerous for so many ways, and any party that has ever had to deal with a charmed cleric or barbarian knows how badly this can go if you can’t break that spell. Forcing disadvantage on a save with every turn you inflict damage means the chances of them failing becomes so much higher.

If the concentration spells go out the window, this makes your party much more dangerous and then helps you to avoid some of the worst and most dangerous magical curve balls that a DM can throw at you.

Benefit #3: If you fail an Intelligence/Wisdom/Charisma saving throw, you can make yourself succeed that save instead. This can be used once and then a Long Rest is required to recharge the ability.

This is the closest to Legendary Saves that a player can get, and it’s a good one. How many times has a fighter or barbarian rushed up to wreck someone’s “stuff” but then was hit with a whammy from a spellcaster? Now they can choose to save and have at least a little bit of time to go to town on magic casters who tend to be squishy…and who don’t want to be up close and personal with melee fighters for any amount of time.

How Does Mage Slayer Feat Measure Up?

Mage Slayer is a great equalizer because there is a very important mechanic to remember which is that martial melee builds have higher hit points and AC while spellcasters are more dangerous but are much easier to hit up close, and they don’t have the hit points to take those attacks.

Mage Slayer lets a martial player simply make a save, meaning they always have the chance to close in for major damage fast, and double the chance of breaking concentration of the spellcaster while doing it. A Barbarian or Fighter with multiple attackers doesn’t need many hits to cut down most spell casters.

This is an outstanding feat that fits in flavor-wise, mechanics-wise, and can work with any type of martial character. It’s also worth noting that with the wording, RAW, damage is damage. A fire spell dropped by a Cleric imposes the same disadvantage. Now talk to your DM because I would rule this as intended for martial combat as opposed to giving magic casters a boost, but it just demands proficiency as a prerequisite – not that the weapon is what you’re using.

So while this is a great feat for Fighters or a great feat for Barbarians, you can easily justify giving this to magic-using classes, as well if your DM does not do the DnD homebrew thing and is going to go with rules as written.

Something to keep in mind with your next build.

Mage Slayer Feat: DnD One Vs 5E

So how do these changes compare to the old 5E Mage Slayer feat? Is this an improvement, a nerfing, or something in the middle? Both had imposing disadvantage on concentration when inflicting damage, so that excellent backbone to this feat stays intact and makes sure that the feat is at least usable in both.

Related Article: 5E Mage Slayer Feat Guide

In the 5E addition when a creature close to you (within 5 feet) casts a spell, you could use your reaction to attack the caster. This was good, but it required you already closing the gap, having your reaction, and dealing with a spellcaster whose concentration hadn’t been broken since you need them to start casting to create it.

That is gone in the OneDnD version of Mage Slayer but you also gain two new things with the OneDnD Mage Slayer: a +1 to either Dexterity or Strength, player’s choice, which is okay but nothing special. Standard half feat stuff.

But then there’s the replacing of having advantage on saving throws against spells cast by creatures within 5 feet of you (that distance really limited the usefulness of this in 5E) with the ability to make a failed saving throw a pass against WIS/INT/CHR.

Many times it only takes saving against one cast to be in a position to do serious, serious damage against a spellcaster so having that automatic pass in the back pocket in case you fail a save is incredibly powerful and puts the OneDnD version over the top.

Who Should Take the Mage Slayer Feat in DnD One?

This is pretty easy. This is a great feat for Barbarians and Fighters in almost all circumstances. Paladins and Rogues should also strongly consider this feat as it gives extra power to them as well as a versatility that makes sense.

Even more interesting is the fact that there are many classes who could argue with taking it as part of a build, especially depending on how a DM rules various points of how the feat works.

Because of that most notable is the fact there are very few classes, mostly the full casters (and not even that considering warlock builds), where you would say they couldn’t or shouldn’t look at this feat.

DnD One Mage Slayer Feat Final Grade

The Mage Slayer feat is an A grade feat. It is an outstanding martial feat that should be strongly considered by every melee build, and even trickier half caster builds where it makes sense. The One DnD Mage Slayer feat is a more complete and well thought out feat that works extremely well in the current system and should be seen very often at table play.

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