If a warlock activates the Maddening Hex eldritch invocation, does it damage all targets cursed by the warlock?

Question

One of the Eldritch Invocations warlocks can take is Maddening Hex (Xanathar's Guide to Everything, p. 57):

(Prerequisite: 5th level, hex spell or a warlock feature that curses)

As a bonus action, you cause a psychic disturbance around the target cursed by your hex spell or by a warlock feature of yours, such as Hexblade’s Curse or Sign of Ill Omen. When you do so, you deal psychic damage to the cursed target and each creature of your choice that you can see within 5 feet of it. The psychic damage equals your Charisma modifier (minimum of 1 damage). To use this invocation, you must be able to see the cursed target, and it must be within 30 feet of you.

The description says "around the target cursed by [hex or a warlock feature]". It does not say "a target" nor does it address the possibility of multiple targets active at a time for you to choose.

If I cast hex on a creature, and curse another creature with Hexblade's Curse, then if I activate Maddening Hex, do both creatures get damaged (and others in their vicinity)?

If this is true, this might be so broken because if the enemies are clumped together they will take a lot of damage!

Answer 1

The intent is that you can only damage one cursed target (and creatures next to it) at a time

The invocation repeatedly refers to a single cursed target

As you note, the Maddening Hex eldritch invocation says (XGtE, p. 57; emphasis mine):

As a bonus action, you cause a psychic disturbance around the target cursed by your hex spell or by a warlock feature of yours [...] When you do so, you deal psychic damage to the cursed target and each creature of your choice that you can see within 5 feet of it. [...] To use this invocation, you must be able to see the cursed target, and it must be within 30 feet of you.

The feature doesn't explicitly say the damage is dealt to only one cursed target, but it repeatedly refers to the target in the singular (i.e. "the [cursed] target", or "it"). This suggests that even if you do have multiple curses active - such as a hex on one creature, and a Hexblade's Curse on another - you simply choose one of these cursed targets when you activate Maddening Hex, dealing the damage to only that creature and other creatures (of your choice) adjacent to it.

Designer intent indicates that Maddening Hex triggers off just one of the creatures you have cursed

Rules designer Jeremy Crawford answered this exact question in an unofficial tweet from November 2017:

For Maddening Hex, does the psychic damage trigger off of every target cursed by you within range, (One creature cursed by Hexblade's Curse and another cursed by the spell Hex, or the like) or only a single cursed target per turn?

Maddening Hex works on one cursed target at a time.

Crawford's unofficial ruling seems to match the wording of the feature. You may have multiple targets cursed at a time using different warlock features and/or the hex spell, but Maddening Hex only activates on one such target. As you point out, it says "the [cursed] target", singular - so even if you've cursed multiple targets, you can only use Maddening Hex to deal damage to one cursed target (and creatures adjacent to that one, of your choice) at a time.