Death Flash. When the darkling dies, nonmagical light flashes out from it in a 10-foot radius as its body and possessions, other than metal or magic objects, burn to ash. Any creature in that area an able to see the bright light must succeed on a DC 10 Constitution saving throw or be blinded until the end of the creature's next turn.   Light Sensitivity. While in bright light, the darkling has disadvantage on attack rolls as well as on Wisdom (Perception) checks that rely on sight.

Death Burn. When the darkling elder dies, magical light flashes out from it in a 10-foot radius as its body and possessions other than metal or magic objects burn to ash. Any creature in that area must make a DC 11 Constitution saving throw. On a failure, the creature takes 7 (2d6) 2d6 radiant damage and, if the creature can see the light, is blinded until the end of its next turn. If the saving throw is successful, the creature takes half the damage and isn't blinded.