Gray stone glare

If I learn the Black Wind Python's trick, whether it is used to attack, to avoid attack, or to escape, it will be an excellent method, without any trace or sign.
Rusk Cunning held the gray stone in his hand, his face changing from gloomy to bright. He wanted to give up, but for the time being his strength had reached a bottleneck, and there was no other way to increase his strength except to move to a higher level. The gray stone in front of him might be his only chance.
After a little hesitation,...