Morichro, which is also referred to as the Touch of Death, represented a very old Jedi skill. Those who were able to use it could quickly diminish the physical processes of their enemies, eventually resulting in death. Only a small number of Jedi Order members were allowed to train in this hazardous skill, and Master Yaddle was among them. When the Sephi Tey Sirrek was facing the Jedi Knight Vildar Mac, he stated that he had become proficient in Morichro, which made Mac consider the ability to be only a legend. Later, Sirrek used biological pheromones to knock Mac out, claiming that he had utilized the technique.
Within the modern Star Wars canon, the first mention of morichro occurred in Star Wars Character Encyclopedia: Updated and Expanded, a reference book from 2016 that was written by Pablo Hidalgo. In the Star Wars Legends storyline, the Force power, although not named, was initially featured in Champions of the Force, a 1994 novel by Kevin J. Anderson that served as the final book in the Star Wars: The Jedi Academy Trilogy. The name Morichro was first used in the article "The Emperor's Pawns," which was released on July 24, 2001 in the fifth issue of the Star Wars Gamer magazine.