Monterrey's HYDRA came together in 1995, initially formed up as a quartet of vocalist / violinist vocalist Marcela Bovio, the guitar pairing of Luis Ortiz and Carlos Aréchica with Jorge Pérez on the drums. Within the year though both guitarists had exited, being replaced by Roberto Quintanilla and in 1997 HYDRA introduced a new rhythm section of bass player Miguel Villarreal and drummer David Vázquez. Keyboard man Alejandro Millán was incorporated in time to record the band's opening demo 'Bosquejo' in 1999. Carlos Martínez took the bass position in 2000.

Marcela Bovio, Roberto Quintanilla and Alejandro Millán would all go on to forge the atmospheric Doom band ELFONIA. Bovio subsequently fronted STREAM OF PASSION.