'Earth Dragon Express' is a means of transportation frequently used by wizards outside the school.
Similar to the metro for commoners, but without tracks, it shuttles through the earth's veins, transformed by alchemy using the corpse of a dead earth dragon. It has many advantages such as convenience, high capacity, low fare, wide reach, and fast speed.
In comparison, airplanes require the construction of massive airports, boarding and deboarding are inconvenient, and they are too conspicuous; while the relatively discreet Big Clock system is expensive and has limited capacity.
So the young wizards of the Atonement Hunting Team adapted to this somewhat unfamiliar mode of transportation under the guidance of their elder, Trident Sword.
Zheng Qing quickly discovered other advantages of this transportation method.
