Karl Roy was the elder brother of Kevin Roy, the lead singer of the band Razorback, and the first cousin of Jose "Judd" Roy III, one of the defense lawyers of the impeachment trial of Philippine Chief Justice Renato Corona. Roy's other siblings are Ralph, Keith, Krys and Kathryn. He was also a cousin of Jack Roy Duavit. His late grandfather, Jose Roy, Sr. was a Senator in the Philippines.
Roy was also a member of the Tau Gamma Phi fraternity.
Roy began his career in the early 1990s as lead singer of the alternative group Advent Call, but did not become well known to the general public until after founding another rock band, P.O.T. in 1996, when the group had hits with "Yugyugan Na" ("Time to shake"), "Panaginip", "Overload" and "Have a Piece of This". Roy was one of the most influential Filipino artist of his time. "Yugyugan Na" was a cover of the song by the band The Philippine Advisors. P.O.T. officially disbanded in 2005. Two years prior, he formed a new group named Kapatid together with Nathan Azarcon (bass), J-Hoon Balbuena (drums), Ira Cruz (guitar) and Chico Molina (guitar). With Kapatid, he released the albums Kapatid (2003) and Luha (2006). Roy's rock image made him a crowd favorite. He was also popularly known for his eccentric behavior while performing on stage. In September 2007, shortly after returning home from the recording of a TV commercial for San Miguel's Red Horse Beer, Roy suffered a stroke, paralyzing the right side of his body. He recovered, however, and rejoined Kapatid.
Roy had a daughter named Ariana Nicole (born 1994), his only child with his ex-girlfriend Maria Nieves San Diego (Yvette). Roy married ex-wife Deena Devries in 2000. Roy was also famous for being an avid tattoo and piercing wearer. He had a wide variety of tattoos and piercing collection all over his body.
Karl Roy died on March 13, 2012, reportedly due to cardiac arrest, although he was diagnosed with pulmonary edema. Prior to his death, he was rushed to the Cardinal Rufino Santos Hospital in San Juan City where he was put in ICU. He is survived by his wife Dena and daughter Ariana. Hours after his death, Roy became the top trending topic on Twitter Philippines. His remains were cremated and his wake was held at the Our Lady of Mount Carmel Shrine in New Manila, Quezon City. On March 18, his urn was transferred to his family mausoleum at the Loyola Memorial Park as the permanent resting place.
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- Concepcion, Pocholo (March 14, 2012). "Rock star Karl Roy, one of local music’s best acts; 43". Philippine Daily Inquirer.
- "Pinoy rock icon Karl Roy dies". ABS-CBN News and Current Affairs. March 13, 2012.
- Casal, Marj (March 13, 2012). "Pinoy rock legend Karl Roy dies at 43". GMA News and Public Affairs.
- Ramos, NR (March 13, 2012). "Karl Roy, Rock Legend Dies". Manila Bulletin.