Karl Brendel is the pseudonym of Karl Genzel (21 March 1871 – 21 August 1925), a schizophrenic outsider artist and one of the "schizophrenic masters" profiled by Hans Prinzhorn in his field-defining work Artistry of the Mentally Ill (1923, in German; English edition 1972).
Brendel was born in central Germany, the son of a freight transporter and one of eight children, attending school through the age of 14 and becoming employed variously as a bricklayer, plasterer, and iron moulder in a foundry.
However, from 1892 on Brendel was sentenced 12 times for assault and battery and property damage, and had to serve a prison term in 1902, at which point his marriage ended.
The first records of his mental illness come from 1906, when the prison doctor noticed megalomaniacal delusions and abnormal physical sensations; Brendel claimed that he has already experienced a sacrificial death, and that he was Jesus Christ.
His favorite subjects for carving were animal reliefs and depictions of his religious hallucinations, particularly the Christ motif.