Phoenix Kirby Laston (nee Riviera, born May 29, 1980) is an American musician from Medora, North Dakota. He is currently the rhythm guitarist for the alternative metal quintet Osmosis, replacing Jeremy Delson, who only appeared on one album and died in November of 2012. He happens to be the only member in the band's history to be engaged; since the year 2011, Phoenix has been married to Australian post-hardcore sextet All's Well That Ends Well's secondary vocalist, Yani Laston.
On June 24, 2013, Phoenix Laston unveiled a new side project, Sandalphon.
- Birth name: Phoenix Kirby Riviera
- Also known as: Firebird, Phoenix, Kirnix
- Born: May 29, 1980 (age 35); Medora, North Dakota, United States
- Genres: Alternative metal, hardcore, progressive metal, jazz fusion
- Occupations: Musician, singer-songwriter
- Instruments: Guitar, alto saxophone, tenor saxophone, vocals
- Years active: 1996-present
- Labels:Season of Mist, Serjical Strike, Century Media, Epitaph