Kaseem Ryan (born August 11, 1972), better known by his stage name Ka, is an American rapper, producer, and firefighter from Brownsville, Brooklyn, New York City, New York.^{[2][3][4][5][6][7]} His solo work has met critical acclaim and he is often noted for his focused concept albums and lyricism.^[8]

He is a former member of the group Natural Elements.^[9] In 1995 he formed the group Nightbreed with his friend Kev.^[10] In 2008, he was re-introduced on GZA's album Pro Tools on the song "Firehouse" and in that same year he released his debut album Iron Works.^[11] In 2012, he released the follow-up Grief Pedigree on his label Iron Works. The album featured a guest appearance by Roc Marciano and was produced by Ka.^[12]

In an August 2016 New York Post story, Ka was identified as a Brooklyn-based FDNY fire captain. The article focuses on his "double life as a hip-hop artist whose songs are peppered with the N-word, drugs, violence and anti-cop lyrics."^[13] In a 2013 interview Ka discussed being a firefighter, saying "I have a full time job and I work all the time. I try to keep that kinda low. I just have a job. It ain't my calling or nothing. It's just my job."^[14]