Does this strict reading of the rules allow both Extra Attack and the Thirsting Blade warlock invocation to be used together?

Question

The warlock's Thirsting Blade eldritch invocation cannot be normally used with the (non-warlock) class feature Extra Attack, since both feature explicitly say you attack twice instead of once. But it seems to me that you could use both features (if you have them) when using Two-Weapon Fighting.

Assume your character is wielding two light weapons, one of which is your pact weapon. You take the Attack action on your turn to attack twice with your non-pact weapon using your Extra Attack class feature.

Then, given the Two-Weapon Fighting rules, you use your bonus action to attack once using your pact weapon this time.

The Two-Weapon Fighting rules (PHB p. 195) state:

When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand.

But since your have the Thirsting Blade invocation, and you used the Attack action, you get to attack twice with your pact weapon.

The Thirsting Blade eldritch invocation (PHB p. 111) says:

You can attack with your pact weapon twice, instead of once, whenever you take the Attack action on your turn.

Does this combo work within the rules, or is there any interaction I'm not aware of?

Answer 1

No.

Or, more specifically, yes, as long as you didn't get those features via multiclassing, which is never.

The multiclassing rules state:

Extra Attack
If you gain the Extra Attack class feature from more than one class, the features don't add together. You can't make more than two attacks with this feature unless it says you do (as the fighter's version of Extra Attack does). Similarly, the warlock's eldritch invocation Thirsting Blade doesn't give you additional attacks if you also have Extra Attack.

Since you only get Extra Attack as a Warlock if you multiclass and you only get Thirsting Blade as a non-Warlock if you multiclass, this rule always applies and you can never use them together.

Furthermore, even if you did find a way to get them both from a single class, you couldn't use them with two-weapon-fighting like that because the bonus action attack from two-weapon fighting isn't an Attack action. You could, however, use them together in that case despite the 'twice' language to get three attacks out of a single attack action without issue: just make your first attack with something other than your pact weapon and then use your pact weapon via Extra Attack and then use it again via Thirsting Blade. Again, though, you can't actually do this because no class has both class features and they don't stack when you multiclass.

Answer 2

Extra Attack from two classes does not stack

As stated in the multiclassing rules.

Extra Attack applies to your Action, not your Bonus Action

Both the Extra Attack feature and the Thirsting Blade feature let you attack twice when making an Attack Action. There are no rules allowing you to take the Attack Action as a Bonus Action.

The Two Weapon Fighting rules give you one attack (with a lowercase "a") as a Bonus Action, with a prerequisite that you have taken the Attack Action (capital "A").

So, you can make three attacks

Extra Attack (from either feature) plus Two Weapon Fighting gives you three attacks in a turn, not four (see How many attacks can a fighter with two-weapon fighting make at 5th level?).

Answer 3

It doesn't work for a couple reasons:

The multiclassing rules outright make Thirsting Blade not do anything if you already have the Extra Attack feature (emphasis mine):

Extra Attack

If you gain the Extra Attack class feature from more than one class, the features don't add together. You can't make more than two attacks with this feature unless it says you do (as the fighter's version of Extra Attack does). Similarly, the warlock's eldritch invocation Thirsting Blade doesn't give you additional attacks if you also have Extra Attack.

(Multiclassing rules from the Basic Rules)

Also, the offhand attack from two-weapon fighting is a separate bonus action, not part of the main Attack action (possibly helpful tangential reading: What does upper-case-A-Attack action vs. lower-case-a-attack mean?). Thirsting Blade specifically says that when taking the Attack action, you can replace one attack with your pact weapon with two instead. The offhand attack is not part of that Attack action, and in your example, you're not making any attacks with the pact weapon as part of the Attack action to trigger Thirsting Blade.

Answer 4

It will not give you three attacks, because it allows you to 'attack with your pact weapon twice, instead of once, whenever you take the Attack action'

However I wanted to add, thirsting Blade does not give an extra attack so the multiclassing rule on extra attack does not factor in here.

Answer 5

Yet a fighter can make two attacks at level five, with extra attack. Warlock thirsting blade says you can attack twice if you use an attack action. What if you have a normal weapon in your main hand and pack blade in your of-hand. Use attack action main hand attack twice, now you have used an attack action. Now your bonus action (having used an attack action) to attack twice per the warlock feature? Am I just reaching here to get 4 attacks per round!

Answer 6

based on what I've read and the wording of the rules I'd say that while you can't use extra attack and thirsting blade to do four attacks with two weapon fighting, you could make a single attack with your main hand non-pact weapon, and follow it up with two attacks from your off hand pact weapon. Why would you want to do this? Not a clue other than just because you can. The reason I'd say this "works" is because TB only say that "You can attack with your pact weapon twice, instead of once, whenever you take the Attack action on your turn." This wording doesn't stipulate that the Attack action has to be with the pact weapon just that you can attack twice with a pact weapon if you've taken the attack action at all. So, in conclusion, as long as you don't have extra attack, which negates having TB completely, you could take the attack action and the attack twice as a bonus action with a pact weapon