Question: Which artist was featured on The Dream Merchant Vol. 2 and was also a part of the duo Black Star.
Context: Train of Thought is the debut album of American hip hop duo Reflection Eternal, released October 17, 2000 on Rawkus Records.  Collaborating as a duo, rapper Talib Kweli and DJ and hip hop producer Hi-Tek recorded the album during 1999 to 2000, following their individual musical work that gained notice in New York's underground scene during the late 1990s.  Kweli had previously worked with rapper Mos Def as the duo Black Star, and Hi-Tek had served as producer on the duo's debut album. The Black Star Line (1919−1922) was a shipping line incorporated by Marcus Garvey, the organizer of the Universal Negro Improvement Association (UNIA), and other members of the UNIA.  The shipping line was created to facilitate the transportation of goods and eventually African Americans throughout the African global economy.  It derived its name from the White Star Line, a line whose success Garvey felt he could duplicate.  Black Star Line became a key part of Garvey's contribution to the Back-to-Africa movement.  It was one among many businesses which the UNIA originated, such as the Universal Printing House, Negro Factories Corporation, and the widely distributed and highly successful "Negro World" weekly newspaper. The Dream Merchant Vol.  2 is the second compilation album from producer 9th Wonder, formerly of Little Brother.  It was released on October 9, 2007 through Sixhole Records.  The album has guest appearances by his former group, Little Brother, his fellow Justus League members, Sean Price, Big Dho, L.E.G.A.C.Y., Chaundon, Skyzoo, Keisha Shontelle, Big Treal, The A.L.L.I.E.S., Jozeemo, Tyler Woods, Joe Scudda, Buckshot, Sean Boog, D.O.X., O-Dash, Buddy Klein & Median, also outside performers (including some who 9th worked with) including Torae, Mos Def, Memphis Bleek, Jean Grae, Royce Da 5'9, Vandalyzm, Naledge (½ of Kidz In The Hall), Saigon, Camp Lo, Ness (of Da Band), Strange Fruit Project & Natural Born Spittas.  The album is also marks the debut of then-unknown MC, Rapsody. Black Star is an American hip hop duo formed in 1997, from Brooklyn, New York City, New York.  The duo is composed of rappers Yasiin Bey (Mos Def) and Talib Kweli.  They released a number of singles and one album, "Mos Def & Talib Kweli Are Black Star" on August 26, 1998.  The record received critical acclaim, but only moderate commercial success.  Since then the duo has worked together intermittently on soundtracks and other projects. Black Star Elephant is the second studio album by Norwegian duo Nico & Vinz.  It was released in Australia on 16 September 2014, and on 14 October 2014 in the United States.  It contains 14 songs and 7 interludes.  The album garnered a mixed reception from critics divided by the production and the duo's socially conscious lyrics.  "Black Star Elephant" debuted at number one in Norway and reached the top 40 in countries like Australia, New Zealand and the United States, spawning four singles: "Am I Wrong", "In Your Arms", "When the Day Comes", and "My Melody". Yasiin Bey ( ) (born Dante Terrell Smith; December 11, 1973), best known by his stage name Mos Def ( ), is an American hip hop recording artist, actor and activist from Brooklyn, New York City, New York.  Best known for his music, Mos Def embarked on his hip hop career in 1994, alongside his siblings in the short-lived rap group Urban Thermo Dynamics (UTD), after which he appeared on albums by Da Bush Babees and De La Soul.  He subsequently formed the duo Black Star, alongside fellow Brooklyn-based rapper Talib Kweli, and they released their eponymous debut album in 1998.  He was featured on the roster of Rawkus Records and in 1999 released his solo debut, "Black on Both Sides".  His debut was followed by "The New Danger" (2004), "True Magic" (2006) and "The Ecstatic" (2009).  The editors at About.com listed him as the 14th greatest emcee of all time on their "50 greatest MC's of our time" list. Dream Merchant Vol.  1 is the first compilation album from producer 9th Wonder, formerly of Little Brother. "Strobelight" is a single from recording artist Kimberley Locke, her first with Randy Jackson's newly formed dance music label, Dream Merchant 21.  This single is also her first release of original material since 2007's Change. The Black Star of Africa is a black five-pointed star (★) symbolizing Africa in general and Ghana in particular.  The Black Star Line, founded in 1919 by Marcus Garvey as part of the Back-to-Africa movement, modelled its name on that of the White Star Line, changing the colour from white to black to symbolise ownership by black people rather than white people.  The black star became a symbol of Pan-Africanism and anti-colonialism.  Described as the "Lodestar of African Freedom", the black star was used in 1957 by Theodosia Okoh in the design of the Flag of Ghana. Mos Def & Talib Kweli Are Black Star (often called simply Black Star) is the only studio album by Black Star, a hip hop duo consisting of emcees Talib Kweli and Mos Def (the latter of whom now goes by his new stage name Yasiin Bey).  The album was released on September 29, 1998, to critical acclaim.  The title is a reference to the Black Star Line, a shipping line founded by Pan-Africanist Marcus Garvey.  The album deals with modern-day issues, philosophical ideas, and life in Brooklyn, New York City, as the two artists know it.
Answer: Mos Def