Stefan Hergli, known professionally as Sero, was born on January 28, 1992, in Berlin-Schöneberg, Germany. He is a German rapper who taught himself freestyling and rapping. In July 2016, he released his first single "Holy" after securing a record deal with Four Music through a three-track demo. His debut album One and Only was released in May 2017, featuring the song "Trigger", which included a collaboration with Avelina Boateng. In August 2018, Sero released his EP Sweet-Tape, followed by another EP titled Raw-Tape in October. His second album, Regen, was released in November 2020. Sero has also ventured into acting, making his debut in the television series Tatort in 2020.