The period from the nineteenth to the twentieth century...

...was a time when methods of warfare evolved rapidly.

Dramatic advances in the accuracy and ammunition capacity of firearms, the replacement of horse-drawn vehicles by automobiles, the advent of wireless technologies and the airplane, the disappearance of cavalry from the battlefield, supplanted by chariots of steel roaming across the plains.

The progress of industrial technology led to the trend of mechanization—

At the same time, the miracles brought by the sacred beasts also promoted "mystic" developments.

Radar technology first appeared during the Second World War, but fell into disuse once noetic control techniques became established. Furthermore, the bodies of Legions had the property of neutralizing radar waves, thus leading to its obsolescence in the modern world. Intelligence gathered by retainer beasts or human observation was more useful.

In addition, aircraft had failed to become the rulers of the skies.

The skies were controlled by flight-capable retainer beasts and the godlike sacred beasts. Workers in the field of aviation would always go about their days in devout fear, watching out for storms and turbulence caused by these beings on whim. One could inflict severe damage upon human aircraft simply by using noetic waves to summon flocks of birds to collide against the cockpit or engines.

It was currently the year 1998 at the end of the twentieth century, an era when mankind was no longer the lord of all creation.