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I am building a rogue-warlock multiclass in D&D 5e. I get advantage using my familiar's Help action. And because it is near me, I can use Sneak Attack as well.

I am thinking about using booming blade. I know you can't make your second attack with booming blade.

So can I make my 1st attack with advantage, then use booming blade, then use Sneak Attack, and after that use Cunning Action to Disengage?
And if my first attack misses, can I make a second attack with my other shortsword and after that use Sneak Attack (I won't use Disengage or booming blade with my second attack)?

V2Blast
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Bay Pacman
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3 Answers3

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Booming blade is a spell and thus does not use the Attack action

The core misunderstanding here, as far as I can tell, is that booming blade is a spell and thus uses the Cast a Spell action and not the Attack action. And you choose which action to take before making the attack. I'll try to run down what works and what doesn't.

To get them out of the way, booming blade and Sneak Attack does work, your familiar can grant andvantage and qualify you for Sneak Attack, and because Cunning action has no restrictions you could use your bonus action to Disengage. Cunning action has no relation to attacks, other than using the same action economy as they (generally) use (as it uses your bonus action).

However, even if the attack misses, you have still taken the Cast a Spell action, and not the Attack action required for Two Weapon Fighting (which is the rule which would let you take an attack with your other weapon as a bonus action). Note that you can only take one bonus action per turn (PHB p. 189), so you could never use two weapon fighting and cunning action of the same turn.

Someone_Evil
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    I am not a native English speaker. So I get little confused. So I am gonna ask and just say yes or no.

    I carry two shortswords. I attacked with the first. It hit I used booming blade and I can damage the target with booming blade (lvl 5) and than disengage. Right?

     – Bay Pacman Jul 04 '21 at 20:59
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    @BayPacman Yes, that part works. That has used your action and bonus action for that turn, leaving you with your movement (and reaction for the round). You technically use booming blade before you hit, but as it costs no resources, it doesn't usually matter much. – Someone_Evil Jul 04 '21 at 21:03
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    @BayPacman: If you cast booming blade, you choose to do that before making any attacks at all; casting booming blade uses the "Cast a Spell" action, not the "Attack" action. As part of booming blade, you make an attack with a weapon. If that weapon attack hits, you do the weapon's damage + Sneak Attack, and the effects of booming blade apply as specified in the spell description (if your total character level is level 5 or higher, the weapon attack does extra thunder damage; otherwise, you only do thunder damage if the target moves willingly before the start of your next turn). – V2Blast Jul 04 '21 at 21:58
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    @BayPacman: If you do cast booming blade, you can't use the Two-Weapon Fighting rule (to make a second attack with your bonus action) - regardless of whether the first attack hits. (In other words: if you cast booming blade, you can only make a single attack.) However, Cunning Action does let you Dash, Disengage, or Hide as a bonus action, regardless of what you do with your action - so you can still do any of those (as long as you haven't already used your bonus action to do something else). – V2Blast Jul 04 '21 at 22:00
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Unfortunately, this does not work

The basic premise is solid, but Booming Blade is the problem for you.

Normally:

  1. You make an attack, using your action; if it hits, you do extra damage from Sneak Attack, and can then Disengage with your bonus action and move away.
  2. If the first attack misses, you swing your second sword, using a bonus action (thanks to the Two-Weapon Fighting rule); if that hits, you would get your Sneak Attack (since you haven't already added the extra damage from Sneak Attack yet this turn).

So far, so good.

The problem is that your bonus-action attack for Two-Weapon Fighting relies on you taking the Attack action, which for you would likely be a single melee weapon attack. Booming Blade, however, uses the Cast a Spell action, rather than the Attack action (capital A). So if you cast Booming Blade, that would not allow you to make a second attack under any circumstances.

This is easily confused, because as part of Booming Blade you do make an attack (lowercase a), but it isn't the Attack action (capital A).

V2Blast
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SeriousBri
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  • Well but if I miss the first attack, than I couldn't even use booming blade right? Because I a remember correctly in order to use booming blade I should hit the target. So can I use the second attack? – Bay Pacman Jul 04 '21 at 21:14
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    @BayPacman if you miss on the first attack you have spent your action and cannot cast Booming Blade. You only get one action per turn. – Joakim M. H. Jul 05 '21 at 07:20
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    @BayPacman Booming Blade is not cast after a target is hit, but it is cast (using the Cast a Spell action) before you make the attack. The weapon attack is then made as part of the spell, but importantly it is not an Attack action. Yes this is confusing and the 5E writers could maybe have done something about it. On this site we tend to use Attack for the action and lower case attack for something that makes an attack roll. It is still confusing though - different rules trigger for the Attack action and individual attacks. – Neil Slater Jul 05 '21 at 14:25
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Let's try taking your idea apart:

I am thinking about using booming blade with booming blade. I know you can't make your second attack with booming blade.

Correct. In fact, you can only make one attack as you're using the "Cast a Spell" action for your Action.

So can I make two rolls(for 1st attack with advantage) than use booming blade, than use sneak attack, after that use cunning action to disengage.

So far so good. As a Rogue, you can use your Bonus Action to disengage.

And if my first attack miss, can I make a second attack with my other shortsword and after that use sneak attack (I won't use disengage or booming blade in second attack)?

Here is were it gets tricky. Two-weapon fighting has two things working against you:

  1. It uses your Bonus Action to get a second attack. But you used that to Disengage.
  2. It requires that you use Attack for your Action. Since you used "Cast a Spell" as your Action, you cannot use two-weapon fighting.

Unfortunately, your plan will not work.

MivaScott
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    Two weapon fighting as a bonus action has taking the attack action as a prerequisite, so while you may or may not have a bonus action free, you can't use it to attack if you used Booming Blade as your action. – SeriousBri Jul 04 '21 at 21:01
  • Thanks I was asking about the last part. I don't think to use my cunning action if I miss the first attack (because without booming blade I don't need to force the enemy to move).

    For rolls part. I have a Imp. Which will be invisible and it will use help action. Flying near to my enemies. Because I will engage in melee, with a ally (imp) I can use sneak attack. And because of it will use help action, both of my attacks will use advantage, so i will roll 2 d20's for first and 2 d20's for second attack? Am I right?

     – Bay Pacman Jul 04 '21 at 21:09
  • @SeriousBri, Good catch. I updated to reflect the need for the Attack Action – MivaScott Jul 04 '21 at 22:00
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    @BayPacman The imp using the help action will only help your first attack. – Joakim M. H. Jul 05 '21 at 07:25