Edit: title was originally “Problem with the wording of the Darkness Bane” but as Great_Moustache pointed out, this was not a mistake or problem with the wording. Title changed to better represent my argument which was a very powerful ability with the darkness boon I noticed that may need to be kept in check by a GM.
I was looking into making an illusionist character with high influence and noticed the darkness boon.
Choose a space or object within range. Darkness emanates from the target to a radius equal to five feet per power level of the boon. The effect cancels the effect of all natural light within its radius of effect and creatures that depend on light for vision suffer as though they have the blinded bane while in the area of effect.
It does not specify any requirements for the object unlike the spell from 5e with the same name. Therefore, one could invoke darkness on an enemy’s clothing or armour and effectively cause a blindness bane that can not be resisted and could take multiple turns to remove. Assuming that the NPC or player was even able to figure out the cause of the blindness. This wouldn’t work on natural foes without equipment or clothing or enemies with blindsight but I still think this ‘boon’ is particularly nasty.
You could easily multi-target up to 5 enemies with influence 5. Sure you’d take huge disadvantage but you would only need to roll a 12 total to get the 5’ radius darkness. This would only require rolling average on the d20 as you’re guaranteed at least plus 2 from the 2 d6s. So an average roll would get you an effect equivalent to multi-targeting blindness which requires beating a defense stat (likely higher than 12) with disadvantage 5. With the added bonus that removing the blinders would likely require at least one turn or losing a valuable piece of equipment.
Now before writing this I misunderstood how the darkness covered the targeted area. With a 5’ radius at the lowest level, this would still imply that the darkness was spreading into the adjacent squares meaning attacking these foes in melee would resulted in you being equivalently blinded. However, you could mitigate this by attacking with ranged or area attacks. The ranged attacks would likely still take a penalty but you’d be more or less safe from counter attack.
If you want to abuse the rules as written be my guest, but I would suggest as GMs that you change the targeted object to be specifically those not being held or worn by unwilling subjects as a house rule.
Edit: typo there, I had “worn by willing” when I meant “worn by unwilling”