Jason C. Medeiros better known as Mr. J. Medeiros, is an American Rapper, Record Producer, and Songwriter.
 As well as releasing music under the name, Mr. J. Medeiros, he is responsible for forming the Hip Hop group The Procussions, is one half of the Hip Hop/Electronic duo AllttA, and the lead singer of Punk-Rap group KNIVES.
 He is of Portuguese and Scottish descent.
 Mr. J. has written music with such artists as, Monte Nueble, Noel Zancanella, Randy Jackson, Marty James, Shad (rapper), George "Spanky" McCurdy, Symbolyc One (S1), Illmind, Benny Cassette, Talib Kweli, 20Syl and French hip hop group Hocus Pocus (group) and more famous C2C.
Ryan Daniel Montgomery (born July 5, 1977), better known by his stage name Royce da 5′9″, is an American rapper from Detroit, Michigan.
 He is best known for his longtime association with Eminem as well as his solo career, recording primarily with producers Carlos "6 July" Broady and DJ Premier, as well as ghostwriting for the likes of Diddy and Dr. Dre.
 Royce is one half of the rap duo Bad Meets Evil with Eminem, one quarter of the hip hop group Slaughterhouse with Joe Budden, Joell Ortiz and Crooked I, and one half of the hip hop group PRhyme with DJ Premier.
 The editors of About.com ranked him No. 30 on their list of the Top 50 MCs of Our Time (1987–2007).
Beautiful Eulogy is a Christian experimental hip hop group and production team from Portland, Oregon, signed to the label Humble Beast.
 Composed of rappers Braille and Odd Thomas and producer Courtland Urbano, the group coalesced in 2011 while the three artists were involved in the creation of Braille's seventh release, "Native Lungs".
 Known for its experimental and eclectic sound, the group melds myriad styles of hip hop with genres such as folk, electronic, hymn tunes, and modern worship music.
 After contributing a song to the charity compilation "King Kulture" and making a guest appearance on Lecrae's "Church Clothes", the band released its debut album, "Satellite Kite", on June 19, 2012.
 A second album, "Instruments of Mercy", came out on October 29, 2013.
 Called one of the most innovative hip hop groups in Portland, Beautiful Eulogy has met with critical acclaim, with particular praise directed at the group's creative, unconventional sound and deep theological lyrics.
Overcast!
 is the debut studio album by Minneapolis hip hop group Atmosphere, released in August 5, 1997 on Rhymesayers Entertainment.
 It's the only Atmosphere album to feature MC Spawn trading verses with Slug.
 Before the album's release, Spawn left the group due to conflicting motives.
Anthony Davis (born September 6, 1970), better known by his stage name Ant, is an American hip hop producer.
 He is best known as being one half of the hip hop group Atmosphere, but has worked with many other artists and projects, mostly with Rhymesayers Entertainment, such as Brother Ali, I Self Devine, Felt and The Dynospectrum.
 He has also released two solo albums, Melodies and Memories, and Melodies and Memories 85–89.
CeCe Winans is the self-titled studio album by award winning gospel artist CeCe Winans.
 The album adopted a more urban flair to it with a mixture of Pop, R&B, and Hip Hop.
 The album itself did rather well.
 The single "Anybody Wanna Pray" included a guest appearance of the Gospel Hip Hop group GRITS.
 Like many urban gospel projects, the album was not without its controversy due to the use of Hip Hop and many other "urban" genres, this has been Winans' most urban album to date.
 Her next release, Throne Room was a much more conservative release.
Lucy Ford: The Atmosphere EP's is a compilation album by the Minneapolis hip hop group Atmosphere.
 It was released on Rhymesayers Entertainment in 2001.
 The album collects the previously released EP's, "Ford One", "Ford Two", and "The Lucy EP".
The album is entirely produced by DJ Kool Akiem.
 Guest appearances include Slug of Atmosphere, Muja Messiah and Malcolm.
Sean Michael Daley (born September 7, 1972), better known by his stage name Slug, is an American rapper from Minneapolis, Minnesota.
 Slug is best known as one half of the hip hop group Atmosphere, which he founded with Derek Turner (Spawn).
 Turner has since left and Anthony Davis (Ant) produces Atmosphere with Slug.
 In 1995, Slug, in collaboration with Anthony Davis, Musab Saad, and Brent Sayers founded the Minneapolis-based independent hip hop record label Rhymesayers Entertainment.
Bizarre Ride II the Pharcyde is the debut album of American hip hop group The Pharcyde, released on November 24, 1992 through Delicious Vinyl Records.
 The album was produced by former group member J-Swift, and features only one guest appearance, provided by little known Los Angeles rapper Bucwheed (known then as "Buckwheat" from The Wascals).
 In the years after its release, "Bizarre Ride" has been hailed by music critics and alternative hip hop fans, as a classic hip hop album along with Souls of Mischief's "93 'til Infinity", and has appeared in numerous publications' "best albums" lists.

Question: Which artist is one half the hip hop group Atmosphere and made a guest appearance on The Emperor & the Assassin?
Answer: Slug