Information:  - Black metal is an extreme subgenre and subculture of heavy metal music. Common traits include fast tempos, a shrieking vocal style, heavily distorted guitars played with tremolo picking, raw (lo-fi) recording, unconventional song structures, and an emphasis on atmosphere. Artists often appear in corpse paint and adopt pseudonyms.  - Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and the United States. With roots in blues rock and psychedelic/acid rock, the bands that created heavy metal developed a thick, massive sound, characterized by highly amplified distortion, extended guitar solos, emphatic beats, and overall loudness. Heavy metal lyrics and performance styles are sometimes associated with aggression and machismo.  - Stian Aarstad is a Norwegian pianist and keyboard player best known for his five - year ( 1992 -- 97 ) stint with the black metal band Dimmu Borgir during which he played keyboards and synthesizers while engendering criticism and controversy for appearing onstage and performing in a top - hat - and - cape outfit reminiscent of Jack the Ripper , while wearing minimal corpse makeup and not moving or showing any emotion . Upon joining Dimmu Borgir , he did n't listen to metal music , preferring only to listen to classical . In 1998 to 1999 , he produced a demo - EP for the unblack metal band Vaakevandring . In the 2000s , Aarstad had been the pianist for the band Enthral , but left his regular position during the recording of the band 's third album .  - Dimmu Borgir (or or ) is a Norwegian symphonic black metal band from Oslo, Norway, formed in 1993. The name is derived from Dimmuborgir, a volcanic formation in Iceland, the name of which means "dark cities" or "dark castles/fortresses" in Icelandic, Faroese and Old Norse. The band has been through numerous lineup changes over the years; guitarist Silenoz and vocalist Shagrath are the only original members who still remain with guitarist Galder being a longstanding member.  - Jack the Ripper is the best known name given to an unidentified serial killer generally believed to have been active in the largely impoverished areas in and around the Whitechapel district of London in 1888. The name "Jack the Ripper" originated in a letter written by someone claiming to be the murderer that was disseminated in the media. The letter is widely believed to have been a hoax and may have been written by journalists in an attempt to heighten interest in the story and increase their newspapers' circulation. The killer was called "the Whitechapel Murderer" as well as "Leather Apron" within the crime case files, as well as in contemporary journalistic accounts.  - Whitechapel is a district in the East End of London, England, in the London Borough of Tower Hamlets.  - London is the capital and most populous city of England and the United Kingdom, as well as the most populous city proper in the European Union. Standing on the River Thames in the south east of the island of Great Britain, London has been a major settlement for two millennia. It was founded by the Romans, who named it "Londinium". London's ancient core, the City of London, largely retains its medieval boundaries. Since at least the 19th century, "London" has also referred to the metropolis around this core, historically split between Middlesex, Essex, Surrey, Kent, and Hertfordshire, which today largely makes up Greater London, governed by the Mayor of London and the London Assembly.  - Dimmuborgir ("dimmu" "dark", "borgir" "cities" or "forts", "castles"); pronounced ) is a large area of unusually shaped lava fields east of Mývatn in Iceland. The Dimmuborgir area is composed of various volcanic caves and rock formations, reminiscent of an ancient collapsed citadel (hence the name). The dramatic structures are one of Iceland's most popular natural tourist attractions.    Given the information, choose the subject and object entities that have the relation of 'country of citizenship'.
The answer to this question is:
stian aarstad , norway