Maximilian is the de-facto second-in-command of the USS Cygnus.
Although he doesn't express what he thinks in words, his sharp stiff body language does the talking. He shows no trust towards strangers especially when they are considered as guests. Even though he is Reinhardt's loyal number one, He's also known to disobey his master's wishes and will do as he pleases when he kills Dr. Durant or ignores Reinhardt's cry for help.
When the crew of the Palomino arrive at the command tower, Maximilian is the first robot to approach them and almost threatens to eliminate them until Dr. Reinhardt orders him to stand down.
He assists Captain Holland, Pizer and V.I.N.CENT in acquiring the parts they need to repair their ship but shows no trust towards the visitors, especially when he catches Holland snooping around the USS Cygnus.
When Kate and Alex try to escape after finding out Reinhardt's dark secret, Maximilian engages them and kills Alex much to Reinhardt's disgust.
When the Cygnus is on the edge of destruction, Reinhardt orders him to prepare the Probe Ship but instead goes after the crew of the Palomino, leaving his master pinned down against a huge monitor. He takes them by surprise and shoots B.O.B.. V.I.N.CENT fights him off while the crew escape to the Probe Ship. He nearly destroys V.I.N.CENT until he drills through his circuitry and lifelessly gets sucked away into the black hole.
Reinhardt and Maximilian are merged together and are last seen standing upon a hellish landscape.
- The Basher Beetleworx takes on the form of Maximilian in Tomorrow City in Epic Mickey.
- Maximillian is cited as one of the inspirations for the Omnidroid in The Incredibles, which was released in 2004.