Piotr Paweł Wiwczarek, also known as Peter, is a Polish musician who is the vocalist and lead guitarist for the death metal band Vader, as the only constant member of the band since its inception. He has also collaborated with Kazimierz "Para" Paraszczuk on his tribute album, Bandid Rockin', and is the producer of several of Vader's releases. He was also the founder and guitarist of a side-project, named Panzer X. Panzer X was active between 2004 and 2007. After giving a single concert in 2012, they disbanded again that same year.