Junker was originally created as a companion for Marah by her mother. Over time Junker began to show an increase in curiosity and an apptitude for engineering. His systems were then upgraded to assist the Professors in their construction of Lightyear. Junker knows every bolt and every wire of the ship. He has detailed files of the ships systems and construction. Along with Professor Jacobs, Junker often works on upgrades to Lightyear adding new feature from time to time.
Junker was included on the Chrono Cadets team because of his knowledge of the ship and its systems, but he also added a personal directive of his own accord. Junker is curious of human behaviors and keeps a personal log of each Chrono Cadet missions and how the cadets interact with each other. He thinks that if he can understand how human children interact with each other he can assist in saving humans from their ultmate fate.