Riki Hyoudo dreams of becoming the strongest fighter in the world—and the first step in his journey is to take on the entirety of his high school's karate team. Donning his signature leopard mask, Riki defeats the members one by one before finishing off the imposing team captain, Baba. As he celebrates his victory, he is met with an unpleasant surprise: his fighting skill has caught the attention of Byoudo, Master of the Dark Realm. Now, Riki faces a slew of opponents from both Earth and the Dark Realm, throwing his life into chaos. With his life on the line, Riki is forced to turn to new-found powers that put his humanity in jeopardy. [Written by MAL Rewrite]