Cassio Audi was born and raised in Sao Paulo, Brazil. He helped found the Brazilian band Viper with some friends in 1985. At the time all of them were either 13 or 14. Besides Audi, the founding members included Pit Passarell, Yves Passarell, Felipe Machado, and Andre Machado. Its sound drew inspiration from the rock bands of Europe in the late 70s and 80s. The newly formed group Cassio Audi had their lives drastically changed when they met with a producer who started recording them. He helped them gain name recognition by putting them on their first tour called SP Project.
Before officially going under the name of Viper, the band recorded two extremely well-received demos. The first of these was called The Killera Sword. In 1987 the produced their first official album, Soldiers of Sunrise. It is still considered one of the greatest albums of all time. It was an instant hit, being featured in top heavy metal magazines all over the world.
In 1989 they put out their second album, Theatre of Fate. He would be its drummer and one of its song composers until that same year when he left to pursue a career in finances.Songs that he had written for the band included “Law of the Sword,” “Soldiers of Sunrise,” and “Princess from Hell.” His music was particularly well known for its unique blend of classical music and metal. During his musical career, he was so influential that he was instrumental in helping Brazilian heavy metal become its own unique sub-genre.