© Wizards of the Coast by Kekai Kotaki

The Sentinel Feat Guide DnD 5e: The Opportunist

Martial combatants can do some pretty amazing things in dungeons & dragons. They have to be able to keep up with magic users that can literally send things to other planes of the universe. 

Not to mention, a martial build is made up of so much more than the class alone. Feats are such an important part to doling out that much more damage. And no other feat creates quite so many opportunities to attack as the sentinel feat does.

What does the Sentinel Feat do?

The sentinel feat allows you to become a vigilant combatant in complete control of your surroundings. It gives you the ability to take more attacks of opportunity, more reaction attacks, and even lets you immobilize foes that try to escape your grasp. 

Sentinel You have mastered techniques to take advantage of every drop in any enemy’s guard, gaining the following benefits.

  • When you hit a creature with an opportunity attack, the creature’s speed becomes 0 for the rest of the turn.
  • Creatures provoke opportunity attacks from you even if they take the Disengage action before leaving your reach.
  • When a creature within 5 feet of you makes an attack against a target other than you (and that target doesn’t have this feat), you can use your reaction to make a melee weapon attack against the attacking creature.

This feat is split into three parts. Let’s take them in one at a time.

The first ability reduces a creature’s speed to 0 when we hit them with an opportunity attack. Opportunity attacks are triggered when a hostile creature you can see moves out of your reach. 

If your reach is 5 feet, as is the typical case, then you would make your attack of opportunity as they attempt to leave that square, and then they’d be completely unable to move for the rest of their turn.

This first ability alone means that you can protect your allies from an incoming attacker, stop a creature from escaping, and get an extra attack in. Doing any one of those things is enough to make you feel like a master of the battlefield, but there are still two abilities left.

The second part of this feat is that you can take opportunity attacks on a creature even if they’ve used the disengage action before leaving your reach. That’s substantial since the only effect disengage has is that it protects a creature from creating opportunity attacks.

So long as a creature is moving out of your reach and you can see them, you’ll be making opportunity attacks. There are still a few rare extenuating circumstances, but for the most part you become an inescapable force.

If a creature teleports or is moved by an outside force (doesn’t use their own movement speed) when leaving your reach they’re still safe.

Putting the first two abilities of this feat together means that almost no one can ever leave your reach. You just need to roll high enough to hit their AC and you’re golden. 

The third part to this feature is interesting. While it is related to the theme of this feat so far, it deals with very different conditions. First off, it talks about a creature making an attack against another target.

This has nothing to do with leaving your reach, like the other two pieces. Instead, you’re reacting to an attack. 

The attack can only be made against a creature that doesn’t also have this feat. Basically, another sentinel doesn’t need you stepping in to protect them I guess? 

The other noteworthy part of the final ability is that it is a reaction attack, not an attack of opportunity. Interestingly enough, opportunity attacks are a type of reaction.

Reactions in general just have to be brought on by some trigger. While the attack in the third ability is triggered by another attack, an opportunity attack, again, is triggered by someone leaving your reach.

It’s really important to remember that these attacks you can make are different because only an opportunity attack can cause a creature’s movement speed to drop down to 0. 

Great Builds for the Sentinel Feat 

Since opportunity attacks are melee attacks, most of the builds that use this feature are going to be melee combatants. Let’s first consider which classes are the best for this feature.

Fighters

Fighters get access to an incredible 7 ASIs over the course of their level progression. This makes it very easy for them to improve their ability scores while still picking up a good amount of feats. In fact, most fighters are going to pick up around 4 feats by the time they reach level 20.

The sentinel feature just makes the fighter better at letting off more attacks. A battle master’s maneuvers would come in handy, since a good amount of them just require you to make an attack, not necessarily on your turn. 

Then, keeping a target in your grasp until your next turn means being able to attack them as much as you want to.

Rogue

While rogues themselves are going to want to avoid coming into contact with this feature, they can benefit greatly from having it. Sneak attacks, the bread and butter of the rogue class, do not need to happen on your turn.

The frequency clause of the sneak attack ability only says you can deal the extra damage once per turn. Not once per round of combat.

So long as you meet the requirements you can use the sentinel feat while dealing some extra damage. In fact, the third ability is automatically going to satisfy one requirement for making a sneak attack, which is that your target is within 5 feet of another enemy (of theirs). 

Monk

Monks are excellent at controlling a situation. Their swiftness and high dexterity let them dance around the battlefield, but they can also do a lot without even moving.

Their stunning attack alone, which lets them stun a creature after they’ve hit them with a melee weapon attack, works beautifully with sentinel in disabling your opponents.

Subclass features like drunken master’s ability to redirect attacks are great ways to supplement this feature, rather than just synergize with it. Being able to create an arsenal of things you can do on your opponent’s turn is how you stay active in combat.

The abilities given to us through the sentinel features also synergize well with other features to make some exciting combos.

War Caster

War caster is a great feat for a half-caster, someone who uses both weapons and spells. The final clause of the spell allows you to make opportunity attacks with spells. Since sentinel makes you the opportunity attack god, you’ll be able to cast a whole lot of spells when it’s not your turn.

Full casters might even opt to pick up both of these feats so that they can continuously cast spells. A pact of the blade warlock or an artificer would benefit well from this feat combo.

Polearm Master

This feature lets you make opportunity attacks whenever a creature enters your reach. It also requires you to use weapons that have the reach property, which increases your reach to 10 ft.

This beautiful combination of feats that whenever a creature enters or exits your 10 foot range you can stop their movement with a precise attack. 

Mage Slayer

Not every creature that finds themselves in a sentinel’s grasps is going to be a martial combatant. This feature gives you some great bonuses against casters that are within 5 feet of you. 

It also allows you to make a melee weapon attack as a reaction to a spell being cast within 5 feet of you. Yet another way for this character to capitalize on other player’s actions. 

There are even some races that work very well with this feature. I’ve pulled together a small list.

Kobold

Their pack tactics feature gives them advantage on attack rolls against a creature so long as an ally is within 5 feet of the creature and is not incapacitated. This gels so well with the third ability of sentinel, meaning you’re going to have such a better chance of letting off hits.

It’s also a great way to strategize, if you can almost always plan to be near an ally you’ll be so likely to have advantage on your opportunity attacks, and therefore a better likelihood of dropping the opponents speed to 0.

Hobgoblin

Hobgoblins get the saving face ability, which allows them to gain a bonus to attack rolls, ability checks, or saving throws when they fail them. That bonus is equal to the number of allies within 30 feet of you, and maxes out at +5.

While you need a short or long rest to replenish this ability, using it to ensure you can stop a creature’s movement in pivotal moments can decide the course of a combat, perhaps even saving an ally’s life.

Grung

I love the grung, so I’ve got to include them. If you’re using a grung monk, specifically if you’re using a grung that uses unarmed strikes, you can poison creatures when they come into contact with your skin.

While this can happen at any time, it’s particularly cool to be able to poison someone just for trying to run away from you.

This is really an amazing feature, and I encourage you to come up with creative ways to use it. Hopefully, this gives you everything you need to utilize these abilities, and opportunity attacks in general, to the highest potential.

As always, happy adventuring!