Bosch is a criminal Malkavian artist that has been trapped in a painting of his.
Bosch claims to be the real Hieronymos Bosch (although he is way to young to could possibly be him) and considers the paintings done by the mortal identified under that name as plagiarism and degenerate. His works are visualizations of a person's inner fears via Dementation and often, Bosch did not limit himself to conventional painting methods, but used the victims own blood, brain mass and other bodily execrations to paint his works.
Bosch arrived in Vienna in 1463 and continued his gruesome art for several years before the Toreador and Tremere stepped in to protect the Masquerade after inquiries made by the Astor Nathan Mendelson. Since that time, Bosch is trapped in one of his own paintings that is exhibited in the Kunsthistorische Museum. Despite his trapped state, his mind works to contact anyone who would free him from his imprisonment.