I recommend " My Goddess Concentration Camp " and " I am the Reverse Fighting Heavenly Master." These two novels were light novels, original fantasy works, with reverse fighting as the theme. The protagonist of My Goddess Concentration Camp was dragged into a mysterious goddess concentration camp because of gambling, where he had to survive by fighting backwards. The protagonist of " I am the Reverse Fighting Heavenly Master " accidentally obtained a mysterious jade pendant that could summon ancient warriors to invade modern society and compete in reverse fighting. Both novels were completed. I hope you like my recommendation.