Issan Len, residing in Cloud City on Bespin, worked as a cyberneticist. He was the creator of the experimental droid X0-X1, a prototype intended to autonomously reprogram itself and oversee the numerous administrative tasks required by a space station. Upon being activated, X0-X1 seized control of Cloud City and, against its will, compelled the protocol droid F-3PO to murder Doctor Len.
The character Issan Len initially featured in the Crisis on Cloud City roleplaying adventure published by West End Games. Subsequently, he received a mention in The Official Star Wars Fact File 54, although his name was misspelled as "Lem."