3 days later, in Castle of Black Iron...
A human flashed in the sky of Castle of Black Iron at a terrifying, high speed like a lightning bolt. People could barely catch his movement by naked eyes even being close to him. Only in the distance could people see a looming grey fine line streaking over the sky...
With a "boom...", a barren 50-m higher hill was exploded into pieces after the human flashed by, sending broken stones flying about 1,500 m in all directions, leaving a huge hole whose depth and radius were both over 10 m.
"Boom...", "Boom...", "Boom..."
The thunder-like explosions sounded one after another. At the same time, those hills at different heights were exploded one after another, leaving many huge and deep holes on the ground. The flying man was like a hypersonic bomber. Wherever he flew over, he would leave a huge, evident trace on the ground.
