During King Alton's reign, the Shadow Lord gained a servant in the Ooze Toad Gellick and created the blister to arm its Grey Guards with projectile versions of its deadly poison. After Gellick subjugated the Dread Gnomes, it forced them to leave large quantities of the poison they harvested by the roadside at the base of the mountain each full moon, as per the bargain it made. Once the Dread Gnomes left, pods of Grey Guards would approach and collect the poison for their weapons. The jars of poison were then carried through a pass to the Shadowlands factory, where they were used to make the blisters.