The group started activities in 2001 the sunny beach of Santos with the release of an independent EP, followed by a national tour that included shows opening for bands like Nightwish and Primal Fear. The hype generated about the band created very high expectations for their official debut full length Theatre of Shadows, released in 2006, an instant national success. They were chosen to support Helloween in their Brazilian tour in 2006. Since then, they have been on the road frequently, having toured Spain twice, USA five times and packed venues in Brazil. Other artists they have performed with are Iron Maiden, Kittie, Divine Heresy, Daath, Temple of Brutality (featuring David Ellefson of Megadeth) and Sepultura.
August 2009 saw the release of Dare to Dream, Shadowside's second album, in Brazil only. The band took a big risk and went for a raw and direct sound. The idea was immediately accepted and embraced by the fans and the album immediately hit position 4 in the Roadie Crew album charts (the most important Brazilian Metal magazine), only below Heaven and Hell, Iron Maiden and Blaze Bayley.
Shadowside is currently being described by the media as “the best band Brazilian band in activity” (Novo Metal website) and as the band that rescued attitude in Rock music (Roadie Crew Magazine). Dare to Dream also received high praise, being picked album of the year by the vast majority of the press in Brazil, top 3 albums by nearly every website and magazine in the country, voted by readers of the Portuguese magazine Horns Up! as the best Brazilian band and by readers of Roadie Crew as best female singer and top 3 overall, top 3 albums, top 3 bands, top 10 guitarists and top 10 live concerts. The album was released worldwide in June 2010.
The band said goodbye to 2010 after an almost 2 months long tour with legendary rock band W.A.S.P. through Europe and entered the studio again in early 2011 to record new material, produced and mixed by Fredrik Nordström (Arch Enemy, Evergrey, Dimmu Borgir, Bring me the Horizon and many more). With the title of Inner Monster Out and lyrics mentioning fears, reactions, personality disorders, although it can be seen at first as a dark album, it also makes it clear that we all have a little bit of crazy and disturbed in a certain way. Featuring special guest appearances of Björn “Speed” Strid (Soilwork), Niklas Isfeldt (Dream Evil) and Mikael Stanne (Dark Tranquillity) on the title-track, the raw energy of all 11 songs show a band that is not afraid to try and push its own limits.