Music from Poland – Gods and Demons

This song , or better these 4 or 5 songs come from Poland , as i could translate the title , the songs have all the same topic , gods and demons in slawonian mysticism , i could not identify the interpreters….. sorry , if someone can help , please don´t hesitate 7

Here , i found a good article about this topic ( in polish ) try to translate it with an online translator