"The pillar of fire just then was really strange." Catherine stared blankly at the tunnel after the flame pillar disappeared, only now noticing some minute differences in the underground cavity, such as the blackened circular walls from burning, some crystallized parts in the cave, and the absence of any fauna and flora around the cave - all of these minute details testified to the sporadic high temperatures here.
"How did these pillars of fire appear?" Vivian searched through her knowledge, but couldn't find a reason, "It can't be a volcanic eruption, nor a combustion, and not an explosion either. So what exactly caused it?"
"Nobody knows." Ike shrugged, "A friend once half-jokingly called them the breath of the King of Hell, which I think is quite fitting. But it's just a joke, and these are not accidents - you can encounter many such fire-erupting spots in these several layers, and the timing of the eruptions is extremely precise; the error would not exceed a minute."
