Midnight Pearl's Deadly Blades skill allows her to roll one extra die when attacking Raiders. If she's attacking multiple Raider types, she chooses the color of the die.
Earthers' Blessed People ability prevents Rangers from using skills or Special cards when fighting them.
So, it seems pretty clear that if Midnight Pearl attacks a location where Earthers are the only Raiders present, she cannot roll the extra die.
But what if Earthers are there along with one or more other Raider types? Can she roll an extra non-yellow die, based on the other Raider(s) present?
Follow-up question: If the answer above is "no" and Midnight Pearl cannot roll any extra dice (even non-yellow) dice when Raiders are part of the attack, does she have the option of only attacking the non-yellow Raiders at the location? (For instance, if there are two Earthers and a Techie at the location, could she just attack the Techie, rolling two dice -- one for the Techie itself and one from her skill?)