The artificer infusion Radiant Weapon has the following property as one of its effects (E:RftLW, p. 62; WGtE, p. 182):
[…] As a reaction immediately after being hit by an attack, the wielder can expend 1 charge and cause the attacker to be blinded until the end of the attacker’s next turn, unless the attacker succeeds on a Constitution saving throw against your spell save DC. […]
This effect does not impose any restriction on what kind of attacker can be blinded by this (e.g. "after being hit by a melee attack" or "an attacker you can see"). However, to me, it seems odd that the weapon can blind a long-ranged attacker or someone who is hidden (and therefore the wielder of the radiant weapon doesn't even know the attacker's position).
Can the artificer infusion Radiant Weapon really blind a ranged or hidden attacker?
Is that really how the infusion works, or am I missing something? I know the official artificer is recent, but is there any errata or Sage Advice about this effect of the infusion?
Best Answer
They are Blinded
Unless the feature offers a specific exception, or there's a general rule, things do what they say they do. No exception is given in the description of Radiant Weapon to creatures that are hidden or ranged attackers either specifically or generally that would prevent them from being blinded by this effect, so it would apply to them as well.
As a counter example, consider the spell Blindness/Deafness:
In the case of this spell, it specifically calls out that they must be both seen and in range. The Radiant Weapon effect does not have such requirements.