Booming Blade 5e – D&D 5th Edition
Booming Blade 5e is a fascinating cantrip. Between somewhat murky language and unclear use-cases, there’s a lot of confusion among the 5e community about how exactly you’re supposed to use the Asmodeus-blasted spell.
Booming Blade 5e’s description reads as follows:
As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and it becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends.
Most of the confusion about its use cases stems from the following fact: if you’re in range to use the cantrip on an enemy, then they’re in range to hit you, so why would they ever move from their position, thereby triggering the damage?
This leads to all kinds of theory-crafting on how to force the target of the spell to move, which inevitably leads to strategies that are either too difficult or too costly (in terms of action economy or combat resources) to be practical.
So, how can a player effectively use Booming Blade 5e in combat?
In order to narrow down potential answers and prevent opinion-based responses, the following criteria define “effective use” of Booming Blade:
- The cantrip is used in a way that guarantees one of the following:
- The target suffers the secondary portion of the damage.
- The player is able to influence the battlefield in such a way that increases their odds of success in some way that does not involve directly dealing damage via the cantrip; e.g. forcing the enemy to move into a desirable location.
- The usage of the cantrip is “economically efficient” with respect to action-economy; i.e. the player is not reducing their effectiveness by choosing this Action over another.
As a Readied Action
One of the problems that melee combatants face once they get an Extra Attack is that an Extra Attack is only usable on your turn. As such you cannot use Extra Attack as a readied action. What you can do, however, is ready Booming Blade 5e and take advantage of the extra attack damage at higher levels.
To encourage the enemy to deal with you
If you are a frontline fighter (such as an eldritch knight, Hexblade blade lock, high elf barbarian) you might prefer the enemy attack you rather than go around you and attack the squishy caster in the back. Depending on your build you might do more damage with an extra attack than with Booming Blade 5e even if the target moves.
What Booming Blade 5e offers, however, is a way to incentivize the enemy to stay put. Sometimes even a regular wizard/sorcerer/warlock might want to be a substitute tank if they managed to avoid damage in earlier combats and the regular tank is low on health.
To prevent the enemy from fleeing/disengaging
There are many enemies that can retreat without provoking opportunity attacks. This can be especially inconvenient if you cannot just follow them (they can fly, they are faster than you). Booming Blade 5e helps keep them nearby so that you can attack them next round.
To harm the enemy if it follows you
This is especially applicable for Arcane Tricksters who can Booming Blade 5e and then disengage but it can be also helpful for someone who is willing to risk an opportunity attack to keep the enemy from following.
For example, you are a warlock facing a bandit. You could disengage but the bandit will just follow you. You could dash but so can the bandit so you will end up in the same situation. But if you booming blade 5e and then retreat and the bandit stays put you can then dash on the next turn and the bandit will be unable to catch up.
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Booming Blade 5e – D&D 5th Edition in 2021
There are a lot of enemies who are fragile, magic casters, sneaky, or ranged fighters. They would love to run and hide if you get into combat. Booming Blade 5e deals extra damage if these targets run, so it can help you control the fight by forcing them to take extra damage, or stay in an unfavourable situation.
Fighting packs of goblins at low levels illustrates this problem. When a goblin gets hurt at all, the cowardly creature is likely to flee or at least try and put distance between themselves and the PC so they can hide and use ranged attacks. Using Booming Blade 5e makes running a less appealing choice, so they are forced to stay and fight and can be easily dispatched.
I have found that Arcane Trickster in particular can make effective use of Booming Blade. An enemy force consisting of tanks, and back liners are vulnerable to rogues. Rogues can easily flank the back liners and take them out with heavy damage.
Enemy back-liners can always choose to run away (maybe disengaging) against a normal rogue, but ATs have familiars and Booming Blade, so if you run away then you can expect Booming Blade 5e damage and a sneak opportunity attack.
The Mobile Feat
This is a perfect use-case for picking up the Mobile feat. It has three attributes to it, but the primary one we care about here is the third one:
- When you make a melee attack against a creature, you don’t provoke opportunity attacks from that creature for the rest of the turn, whether you hit or not.
This is similar to the Fancy Footwork feature of the Swashbuckler Rogue. It allows you to freely disengage from an enemy after an attack, regardless of whether you hit or not. Mobile also grants an extra 10ft of movement, giving you more versatility in approaching, attacking, then putting distance between yourself and the target.
When combined with Booming Blade 5e, this means you can get a free disengage after the attack, forcing the creature to either take the damage or else be limited in its options the following turn. Mobile has good general-use buffs that synergize well with most classes and requires no additional actions (and in some cases such as Rogues and Monks, can save them their bonus action by giving free disengage from the target), meaning the opportunity cost is minimal.
I’ve used the Booming Blade/Mobile combo on both a Bladesinger Wizard and an Arcane Trickster Rogue, and both were able to use the spell very effectively. Combined with a Druid party member who had Moonbeam, we were able to consistently force enemies to take damage whether or not they moved.
You cannot guarantee the extra damage (there are no guarantees in life). It’s a risk like everything else.
So why use it?
Because it potential extra damage
This spell is the domain of Sorcerers, Warlocks, Wizards. These classes do not have a natural Extra Attack in a round 1. Meaning that when they attack with a weapon, they only get one shot. So adding a little extra potential damage is not a bad thing. Also remember, beyond the early levels, it does add extra damage no matter what. Moving just adds to it.
It’s just a cantrip
Since it’s a cantrip, you can cast this every round and also team it up with any of the bonus action “Smite” spells for even more damage for the initial attack.
It’s great for “tanking” type characters.
Picture an enemy that wants to get at someone in the back. One hit from you and now they have a serious choice to make:
- Keep moving and suffer the extra damage
- Stay put and face the attacker
It’s similar to the Sentinel feat that forces someone to stop moving. It is for battlefield control.
1 There are ways to get Wizard cantrips through the race, subclass, domain, and such. So this may not apply to everyone, but it’s a good general consideration.