Princess Mari's childhood roboid tutor. Microtron could be serious, especially when Princess Mari or later his love Nanotron were in danger, but was generally something of a joker. Microtron and Nanotron sacrificed themselves so that their memories could be incorporated into a giant duplicate of the late Biotron, which would serve as the Micronauts' ship after Endeavor was destroyed.
A second Microtron was later created to accompany the Micronauts on their new voyages, but it had little of the original's charm.
Microtron and Biotron became somewhat of the Micronauts' comedy relief in the tradition of Abbott and Costello and Laurel and Hardy.