If it makes you happy...Well the most generic description would be Viking Metal (except the first album which is Black Metal) with some acoustic passages, plenty of melody, elements of progressive metal and a fair amount of keys. all the instruments are quite technical, either in structure orarrangements and vocals vary from clean sung and epic to harsh rasps and shreiks. Not as barmy as Finntroll of as folky as Thyrfing but more technical than either. Like I say this is a rough description and each album is different in its own way.