Forbidden was part of the second wave of thrash metal bands which arose from the bay area thrash scene (along with Testament, Death Angel, Vio-Lence, etc.)

Originally formed in 1985 as Forbidden Evil by vocalist Russ Anderson, guitarists Robb Flynn and Craig Locifero, bassist Matt Camacho, and drummer Paul Bostaph, the group slugged it out around the Bay Area club scene like hundreds of other up-and-coming garage bands inspired by thrash originators like Metallica, Slayer, and especially Exodus. Flynn wouldn't last long (going on to form Vio-Lence, then Machine Head), but with his replacement, Glen Alvelais, the band gradually built a following and eventually signed with Combat Records. Their 1988 debut, Forbidden Evil, received largely favorable reviews and they set out on the road with fellow thrashers Exodus, Death Angel, and Testament. Forbidden then recorded a live EP at the 1989 Dynamo Festival in Eindhoven, entitled Raw Evil: Live at the Dynamo. But unlike their friends Testament, who had successfully pulled off the same stunt two years earlier and solidified their footing with European audiences in the process, the record won them few new fans.

Guitarist Alvelais quit to join Testament shortly before the recording of 1990's Twisted Into Form -- a less inspired but more focused collection of technical thrash, which still failed to break new ground. Then, like many of their peers, Forbidden fell prey to the dwindling interest in thrash metal symptomatic of the early '90s, and a 1992 best-of collection called Point Of No Return seemed like the end of the road. Yet the band persisted, despite their near-obscurity and the defection of drummer Bostaph to Slayer in 1994. New drummer Steve Jacobs joined the group for 1995's Distortion and the band broke up shortly after the release of 1997's Green. Guitarist Calvert went on to join metal band Nevermore, while Locicero, Camacho, and Jacobs formed Manmade God.

Forbidden recently announced that they would reform with the a reborn Forbidden lineup, after years of demand from the fanbase, and play several shows throughout 2023 with new music planned for 2024 as well as festivals worldwide.