[Kaiser2]

Wait, I got it, this can be done to release summons! Like, the warriors (Mages mostly, since no swords and armor) enter the area, after mining through the tunnel. At the end, there is a large "Crystal of the Spirits" which is protected by the combined spirit energy of all the monsters in the caves. The mages split up, traversing the caves, destroying all monsters that they come across, and once they have destroyed all monsters, a message will appear, saying something like "The Spirit Barrier has crumbled! Now destroy the Crystal of the Spirits!" At that point, a timer comes up, and the mages must cast their spells to destroy the Crystal (Make the crystal have a lot of health). Then, when the Crystal is shattered, the spirits of the summon spells rest to reside in the mages, granting all the mages of the world the ability to summon monsters for their beck and call...