Mister Schmitz (originally named Mister Smith in the Japanese version) is a character in Sonic X. He is an old, retired man and a former agent of Guardian Units of Nations who shot and killed Maria Robotnik fifty years ago on the Space Colony ARK.
50 years ago, Mister Smith was a G.U.N. agent. He and his fellow troops were called onto the space station to eliminate or capture anyone related to Project Shadow and ordered the scientists to put their hands up without any explanation as he and the G.U.N. agents did what they were told. Suddenly, he spotted Maria Robotnik, who ran away from the scene as Mister Smith told her to stop. He eventually found her with her hands on a handle switch, intending to release the creature and set him free. Despite him pointing his gun at Maria and warning her not to pull on the handle or he would fire, she did the deed. (In the Japanese version, Mister Smith is then seen firing his gun directly at her).
Scarlet Garcia and Mister Stewart visited a retirement center to interview Mister Smith who is one of the few that witnessed the events of Space Colony ARK 50 years ago. At first, he refused to tell anything about the events of the ARK to Scarlet and Mr. Stewart, much to Scarlet's disgrace. Soon, Mister Schmitz helped combat the black-suited agents that ambushed Mr. Stewart and Scarlet later on. He then finally told the story of his experience at the ARK 50 years ago as a G.U.N. agent. After telling his story, Mister Smith became tearful and guilt-ridden over sealing Maria's fate. He watched the battle in space with Super Sonic, Super Shadow and the Final Lizard.