Uli der Fehlerteufel

Uli was created by teacher Ilse Herrndobler during her work in the 1960s as a pedagogical device for primary-school exercises. The character was used across roughly 40 primary-school books published in the following decades and was adapted into children’s stories (Fehlerteufelgeschichten) written by Ellis Kaut with illustrations by Franz Josef Ott in 1974.

In schoolbooks Uli is depicted as a rotund little red devil with blue-black hair. His full name, Ulimantulus Irrichmich, is a pun pronounced like the German phrase 'Irr ich mich' ('Am I wrong?'), linking the familiar diminutive 'Uli' (short for Ulrich) to his role as a personable, non-threatening figure designed to engage children.

Uli functions as a narrative and pedagogical device: exercises present texts 'affected' by Uli in which, for example, capital letters or punctuation marks are omitted and pupils are asked to restore them. Sources emphasize that this is a didactic portrayal rather than claims of actual supernatural agency. Comparisons in the sources liken Uli to generic figures such as the Typo Fairy/Typo Demon and to the medieval Titivillus in role (personifying textual errors), while noting Uli is a single defined character used for instruction.