Background: Nasir bin Olu Dara Jones was born on September 14, 1973, in Brooklyn, New York. His father, Olu Dara (born Charles Jones III), is a jazz and blues musician, from Mississippi. His mother, Fannie Ann (Little) Jones, was a Postal Service worker from North Carolina. He has one sibling, a brother named Jabari Fret who is best known as "Jungle", a member of the hip-hop group Bravehearts.
Context: Columbia Records began to press Nas to work towards more commercial topics, such as that of The Notorious B.I.G., who had become successful by releasing street singles that still retained radio-friendly appeal. In 1995, Nas did guest performances on the albums Doe or Die by AZ, The Infamous by The Infamous Mobb Deep, Only Built 4 Cuban Linx by Raekwon and 4,5,6 by Kool G Rap. Nas also parted ways with manager MC Serch, enlisted Steve Stoute, and began preparation for his second LP, It Was Written, consciously working towards a crossover-oriented sound. It Was Written, chiefly produced by Tone and Poke of Trackmasters, was released in mid-1996. Two singles, "If I Ruled the World (Imagine That)" (featuring Lauryn Hill of The Fugees) and "Street Dreams", including a remix with R. Kelly were instant hits. These songs were promoted by big-budget music videos directed by Hype Williams, making Nas a common name among mainstream hip-hop. It Was Written featured the debut of The Firm, a supergroup consisting of Nas, AZ, Foxy Brown, and Cormega. The album also expanded on Nas's Escobar persona, who lived a Scarface/Casino-esque lifestyle. On the other hand, references to Scarface protagonist Tony Montana notwithstanding, Illmatic was more about his early life growing up in the projects.  Signed to Dr. Dre's Aftermath Entertainment label, The Firm began working on their debut album. Halfway through the production of the album, Cormega was fired from the group by Steve Stoute, who had unsuccessfully attempted to force Cormega to sign a deal with his management company. Cormega subsequently became one of Nas's most vocal opponents and released a number of underground hip hop singles "dissing" Nas, Stoute, and Nature, who replaced Cormega as the fourth member of The Firm. Nas, Foxy Brown, AZ, and Nature Present The Firm: The Album was finally released in 1997 to mixed reviews. The album failed to live up to its expected sales, despite being certified platinum, and the members of the group disbanded to go their separate ways.  During this period, Nas was one of four rappers (the others being B-Real, KRS-One and RBX) in the hip-hop supergroup Group Therapy, who appeared on the song "East Coast/West Coast Killas" from Dr. Dre Presents the Aftermath.
Question: How was Nas involved in the firm?. Whats the answer?
a supergroup consisting of Nas, AZ, Foxy Brown, and Cormega.