Opportunity attacks, or attacks of opportunity, have been a signature mechanic of Dungeons & Dragons combat since second edition, but 5e opportunity attacks work a bit differently from some prior editions and many players still handle them incorrectly. The mechanic did not appear in the original rules of 2e Advanced Dungeons & Dragons but was added in the Combat & Tactics supplement. The long-running 3e DnD rules built off of Combat & Tactics, integrating many of its concepts into the core rules of DnD. Opportunity attacks make battles more complex and interesting, and understanding them is important, which for some players involves moving past old habits from earlier editions.
Classes like DnD’s barbarian and fighter are more fun than some players think, and playing an effective melee character may require more tactical decisions than playing a spellcaster, especially where opportunity attacks are concerned. Opportunity attacks make positioning and movement important, as characters cannot simply run past their foes to close with whoever they wish. A character with a high armor class and hit points can more effectively protect vulnerable allies, thanks to opportunity attacks. Where the tactical focus of a spellcaster tends to happen before a fight, as they prepare the most useful spells, a melee specialist needs to focus on in-battle positioning and taking advantage of opportunity attacks.
How Attacks Of Opportunity Work In D&D 5e
In 3e and 4e DnD opportunity attacks were triggered when an enemy left a threatened square. The 5e approach is different, as the attack only happens when the foe leaves an enemy’s entire threatened reach. This leads to some bizarre rule interactions, and as strange as some DnD campaign settings are, the rules can seem stranger. A player can freely run circles around a monster, so long as they do not leave their threatened reach. Monsters with various natural weapons can only ever make an opportunity attack with the one that has the longest reach, so many 5e DnD dragons, for instance, can only make opportunity attacks with their tail whip.
Reach weapons are very different in 5e DnD as they allow a foe a wider area to freely move around in without incurring the risk of an opportunity attack. The Polearm Master feat can restore some of the tactical efficacy of glaives and halberds, making feat selection more crucial for martial characters than spell users. Other feats can synergize the effectiveness of opportunity attacks, such as Sentinel, which lets those attacks stop an enemy’s movement. A key limitation is that opportunity attacks use a character’s Reaction. There are DnD 3e and 4e rules 5e is missing, and those include official ways to increase the number of opportunity attacks available.
Characters are limited to one Reaction per round, which means they can only take a single opportunity attack. In 3e DnD, characters could increase their opportunity attacks per round with the Combat Reflexes feat. The 4e rules were even more generous, as they allowed for one opportunity attack per turn, not per round. Between the Reaction limitation and the change from threatened square to threatened reach, opportunity attacks are less effective in the current rules than they have been in the past. That does not mean that players should ignore them, however, as there are still ways to optimize opportunity attacks.
Opportunity Attacks Can Benefit D&D Rogues & Wizards With The Right Feats
A melee rogue can deliver a second sneak attack per round if they perform one on their own turn and a second as an opportunity attack. Many DnD rogues can do twice as much damage if they build towards using their Reaction to deliver a sneak attack during someone else’s turn, and opportunity attacks are one way to do that. Feat synergy comes into play, as Sentinel can stop movement, and Warcaster can allow a spellcaster to replace a melee attack with certain spells for their opportunity attack. Characters with high melee damage, particularly those with the Great Weapon Master feat, deliver more game-changing opportunity attacks.
For most DnD fans, opportunity attacks are an iconic element of the game every bit as much as the magic missile spell. For those gaming groups that still prefer theater of the mind combat instead of using a grid map for battles, opportunity attacks may be less of a factor. DnD has encouraged the use of maps heavily since 3e, and though 5e has simplified the rules, grid maps are still the best way to play. One D&D has changed its critical hit rules repeatedly during its playtest, but grid map play is unlikely to go away with the upcoming 5.5 revision.
Adapting to map play improves many elements of combat in DnD, as it eliminates ambiguity on the area spells can impact or whether an enemy is within range of a longbow. Maps make opportunity attacks come up more consistently, and they help players think in terms of the area they threaten rather than just the enemies they can reach. The opportunity attack mechanic also helps with player engagement, since players need to judge the best use for their one Reaction, instead of tuning out and ignoring the combat until it is their turn again. They may be less useful than in the prior editions, but opportunity attacks remain important.
D&D 5e Opportunity Attacks Can Still Be Optimized
In very high-level games the Cavalier fighter subclass operates like a 4e character where opportunity attacks are concerned. The DnD subclasses to try in future campaigns should include Cavalier, for players interested in maximizing opportunity attacks. At level 18 a Cavalier learns Vigilant Defender, where they receive a “special reaction” they can use on every other creature’s turn in order to take an opportunity attack, solely. For groups that allow Unearthed Arcana playtest content, Tunnel Fighter offers an easier method, available at level 1, where a fighter can enter a stance where opportunity attacks do not use up their Reaction.
To adequately protect weaker party members with opportunity attacks positioning is key. A fighter with a five-foot reach weapon like a Greataxe or Maul will want to stand two squares in front of a vulnerable spellcaster, forcing enemies to go beyond their reach to attack the group’s wizard or cleric. A ten-foot reach weapon user will need to be three squares in front of casters, since their larger threatened reach allows for more enemy movement. The optimized DnD polearm wielding barbarian build has more options, as they can use Polearm Master to attack enemies as they enter their reach instead of only when they leave.
While players will generally want to be wary of opportunity attacks from monsters, knowing when to risk provoking such an attack is also an important judgment call. Some monsters’ opportunity attacks are not worth fearing, particularly for a barbarian in rage who resists most melee damage. There are monsters with unique and powerful Reaction abilities and baiting them into wasting their sole Reaction on an opportunity attack could be beneficial. Opportunity attacks make Dungeons & Dragons more tactical, and add to player engagement, making them one rule no group should ignore.
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