Kent Isaacs has been known to work with an American rapper who is the "de facto" leader of what?
Kent (Gillström) Isaacs: Kent Isaacs, a Swedish producer, mixer, musician, songwriter and music-entrepreneur, is co-owner and operator of Cosmos Music Group, an independent Scandinavian music company. Kent (Gillström) Isaacs:  Isaacs has been known to work with Robyn, RZA, Slick Rick, Yusuf Islam (Cat Stevens), Clay Aiken, Eagle Eye Cherry, Infinite Mass, Arnthor and Stina Nordenstam (showcased on the hit 1996 soundtrack to "Romeo + Juliet"). RZA: Robert Fitzgerald Diggs (born July 5, 1969), better known by his stage name RZA ( "rizza"), is an American rapper, record producer, musician, actor, filmmaker and author. RZA:  A prominent figure in hip hop, RZA is the "de facto" leader of the Wu-Tang Clan.
the Wu-Tang Clan