Souken Tsukai no Lost Magika

A group of young individuals had been summoned to another world and often returned to Earth with retained abilities. A rift appeared above Tokyo as a black fog that engulfed the city, from which a monstrous entity emerged and caused widespread destruction, sealing the rift in the process. Those who had returned from other worlds learned that Tokyo could be freed by destroying massive, nearly indestructible pillars supporting the fog. The most powerful among them engaged in intense combat to eliminate the black fog. A significant presence remained concealed deep within the fog.