Mroczni Bracia Grom (Gloomy Brotherhood of Thunder ;p) are a band that plays probably all genres of music - from techno and rap, through disco and industrial to the most heavy and gloomy kinds of metal. Their music is received as a joke, but in fact their songs are very serious. They have released two studio albums: "G(r)ejtest lowsongs vol. 69" (title is a reference to HIM's album "Greatest lovesongs vol. 666" and "X Krąg Piekła" (The 10th Circle of Hell).