In this task, you are given a set of context paragraph and some supporting facts to answer a question. Your task is to generate answer for given question based on set of context paragraphs and supporting facts.

Context_1 : Sakari "Zachary, Saku" Hietala (born August 10, 1962 in Tervo, Finland) is guitarist, co-songwriter and founding member of Finnish heavy metal band "Tarot" (formerly "Purgatory") in early 80's, together with his younger brother Marco Hietala, who joined "Nightwish" in 2001. Zachary works as a youth instructor in his hometown, Kuopio, as well as teaching music theory to ninth and tenth grade students, and takes part in the management of the official "Tarot" website, responding to questions and comments made by fans on the forum. Zachary is friendly and fun loving . Context_2 : Nightwish is a symphonic metal band from Kitee, Finland. The band was formed in 1996 by lead songwriter and keyboardist Tuomas Holopainen, guitarist Emppu Vuorinen, and former lead singer Tarja Turunen. The band soon picked up drummer Jukka Nevalainen, and then bassist Sami Vanska after the release of their debut album, "Angels Fall First" (1997). In 2001, Vanska was replaced by Marco Hietala, who also took over the male vocalist role previously filled by Holopainen or guest singers. Context_3 : Sapattivuosi is a Finnish Black Sabbath tribute band singing in Finnish. The band was initiated as a project by vocalist Hannu Paloniemi, drummer Simo Vehmas, and guitarist Janne Halmkrona (also of CMX). Sapattivuosi's first two albums covered songs from the Ozzy Osbourne era. Then vocalist Paloniemi left the band. He was replaced by Marco Hietala, known from bands such as Nightwish, Tarot and Northern Kings. Hietala first appeared with Sapattivuosi on their single "Pelon lait" (a cover of "Neon Knights"), which came out on March 4, 2009. The band's third full-length album, "Ihmisen merkki", also covers songs from Black Sabbath's Ronnie James Dio era. It was released on April 1, 2009. Context_4 : Planet Hell is a song played by the Finnish symphonic metal band Nightwish. The song was recorded for their 2004 album "Once". Though it is known as a symphonic metal song, many argue it as falling under the gothic metal category. The song begins with a male choir chanting "Ah" (in an introduction reminiscent of Dark Chest of Wonders), with orchestral background music for a full minute before the band starts playing. Planet Hell also features the vocals of the bands bassplayer Marco Hietala. It is the Nightwish song in which Hietala gets to use his vocals the most. Context_5 : Jarkko Kalevi Ahola (Toijala, 24 August 1977) is a performing artist, a composer and a singer. He is the vocalist and bass player and one of the three songwriters of the band Terasbetoni. He is also a member of a Finnish symphonic metal cover supergroup Northern Kings together with Marco Hietala from Nightwish, Tarot and Sapattivuosi, Tony Kakko from Sonata Arctica and Juha-Pekka Leppaluoto from Charon and Harmaja. Context_6 : The discography of the Finnish symphonic metal band Nightwish consists of eight studio albums, one extended play, four live albums, seven compilations, thirteen music videos and twenty one singles. The band was formed in 1996 by songwriter and keyboardist Tuomas Holopainen, guitarist Emppu Vuorinen, and former vocalist Tarja Turunen; Nightwish's current line-up has six members although Turunen has been replaced by Anette Olzon, and the original bassist, Sami Vanska, has been replaced by Marco Hietala, who also took over the male vocalist part. Olzon left the band in 2012 and was replaced by Floor Jansen. Context_7 : We Are the Others is the third full-length album by the Dutch symphonic metal band Delain. It was released in the Benelux and Germany on June 1 and in the United Kingdom and France on June 4, 2012, by CNR Music, who took over Delain when Warner Music refused to release "We Are the Others". The first single, "Get the Devil Out of Me", was released on April 13. The second single "We Are The Others" and its video was released on September 11, 2012. This is the first album by Delain without any studio songs with guest vocalist Marco Hietala. Live versions of "The Gathering" and "Control the Storm" are featured on the special edition of the album with Marco singing his parts live. Context_8 : Fire-Hearted is the third studio album by metal musician Elias Viljanen as solo artist. The album features Marco Hietala (Nightwish, Tarot, Northern Kings) and Tony Kakko (Sonata Arctica, Northern Kings) on vocals. Also contributing is Jari Kainulainen (Evergrey, Ex-Stratovarius) on bass, Henrik Klingenberg (Sonata Arctica) on keyboards and Mikko Siren (Apocalyptica) on drums. The album was out in June 2009. The song "Last Breath of Love" with Marco on vocals can be heard on Elias' Myspace together with the title-track. Context_9 : "While Your Lips Are Still Red" is a 2007 song written by Tuomas Holopainen and Marco Hietala of the Finnish metal quintet Nightwish. It was performed by Holopainen, Hietala, and Jukka Nevalainen for the Finnish film "Lieksa!", which was written and directed by renowned Finnish director Markku Polonen; the film premiered in Finland in September 2007. The song is included on Nightwish's "Amaranth" single, which was released on 22 August 2007 as the second single of their sixth studio album, "Dark Passion Play". It was also released on their live / compilation EP "Made in Hong Kong (And in Various Other Places)" in 2009. Context_10 : Marko Tapani "Marco" Hietala (born 14 January 1966) is a Finnish heavy metal vocalist, bass guitarist and songwriter. Internationally, he is most known as the current bass guitarist, male vocalist and secondary composer to Tuomas Holopainen, of the symphonic metal band Nightwish. He is also the vocalist and bassist as well as composer and lyricist for the heavy metal band Tarot. fact_1 : Internationally, he is most known as the current bass guitarist, male vocalist and secondary composer to Tuomas Holopainen, of the symphonic metal band Nightwish. fact_2 : The band was formed in 1996 by lead songwriter and keyboardist Tuomas Holopainen, guitarist Emppu Vuorinen, and former lead singer Tarja Turunen. Question: Marco Hietala is a member of a band that was formed when?
1996