Titivillus

Titivillus was a demon said to work on behalf of Belphegor, Lucifer or Satan to introduce errors into the work of scribes. The first reference to Titivillus by name occurred in Tractatus de Penitentia, c. 1285, by Johannes Galensis, John of Wales. 

Titivillus has also been described as collecting idle chat that occurs during church service, and mispronounced, mumbled or skipped words of the service, to take to Hell to be counted against the offenders.

He has been called the "patron demon of scribes," as Titivillus provides an easy excuse for the errors that are bound to creep into manuscripts as they are copied.

(...)

Según parece, Titivillus era el demonio al que Satán le encomendó introducir errores en el trabajo de los escribas. 

Por lo tanto, debería ser el santo patrono (?) de los correctores...

¡Alabado sea, en todo caso, por ayudarnos a llevar el pan ázimo a nuestras mesas!

(Debo la referencia a Javier H. Marín, @Marinjav, y el texto, por supuesto, a la Wikipedia, donde se puede seguir leyendo.)