Spanish hard rock band, founded in 1979 by Tony Urbano (bass, later on Leño, and replaced by Juan Márquez) and Armando and Carlos de Castro (guitars). It was a pioneer hard rock band but their label wanted more commercial songs, so they released Más Sexy, a hard-pop hit that made brothers Armando and Carlos de Castro split-up to found Barón Rojo.

1974 (First stage until the formation of the group Kafru):
Jesús Albeniz, (vocals)
Kanguro (guitar and vocals)
Juan Márquez (bass and vocals)
Miguelo Jiménez (drums)

1976 (Reorganisation of the band, after the dissolution of the group Kafru):
Armando de Castro (guitar)
Carlos de Castro (vocals and guitar)
Juan Toro (bass)
Julio César Narpias (drums)

1977:
Armando de Castro (guitar)
Carlos de Castro (vocals and guitar)
Tony Urbano (bass)
Ramiro Penas (drums)

1978:
Armando de Castro (vocals and guitar)
Carlos de Castro (vocals and guitar)
Tony Urbano (bass)
Paco García (drums)

1979:
Armando de Castro (guitar)
Carlos de Castro (vocals and guitar)
Juan Márquez (vocals and bass)
Jose Luis de la Puente Cutu (drums)

1981:
Juan Márquez (vocals and bass)
Jose Luis de la Puente Cutu(drums)
Eduardo Pinilla (guitar)
Tony de Juan (guitar)

1985:
Juan Márquez (vocals and bass)
Enrique Ballesteros (drums)
Eduardo Pinilla (guitar)
Tony de Juan (guitar)
J. C. Redondo Snoopy (keyboards)

2005 to 2017:
Juan Márquez (vocals and bass)
Enrique Ballesteros (drums)
Miguel A. López Cachorro (guitar) - Miguel Ángel López Escámez (guitar)
Dani Moreno (guitar)
J. C. Redondo Snoopy (keyboards)

From 2018 to present:
Juan Márquez (vocals and bass)
Miguel Ángel López Escámez (guitar)
Dani Moreno (guitar)
Snoopy Redondo (keyboards)
Luis Garcés (drums)

Other members who have been part of Coz:
Napy Antonio G. Tejada (guitar)
Javier Mira (guest guitar)
Juan Olmos (keyboard player and vocals)
Manolo Caño (drums)
Teo Suazo (drums)

Other musicians or singers who have collaborated with Coz:
Fortu (Obús)
José Carlos Molina (Ñú)
Carlos Pina (Panzer)
Jesús Aripont (Def con Dos)
Juanjo Valmorisco (PVP)
Juan Olmos (Antigua)
Valentín del Moral (Chino Banzai)
Raúl Abad (Desenkajaos)
Bárbara Black
José Luis Jiménez (Topo)
Lele Laina (Topo)
Pancho Martín (Bella Bestia)
Isaac Palón (Viga)
Andrew Carlos Redondo

Discography:
# 1980 - Más Sexy
# 1981 - Las chicas son guerreras
# 1982 - Duro
# 1984 - Romper la red
# 1986 - Legítima defensa
# 1989 - Travesura
# 1998 - Hasta que las muerte nos separe (compilation);
# 2006 - Amigo mío
# 2008 - Revuelta