Martin, voiced by Chika Sakamoto in Japanese and Cindy Robinson in English, was one of the boys whom Johan taught his "special game" to. The "game" involved two children standing on the ledge of a building with their eyes closed, walking towards each other. If they made it that far, they would try to push the other off. The winners were those who survived, not just those who didn't fall. Martin ended up in the hospital after failing to stay on the building's rooftop. Dr. Reichwein frequently visited him, but often spent more time comforting Martin's mother than interacting with Martin himself.
Dieter sneaked into Martin's hospital room, and together they wandered out. While walking, Martin mentioned that everything in the world was boring except for the "game," and tried to explain its rules to Dieter. Dieter didn't quite understand, so Martin took him to a rooftop to demonstrate better and attempted to force Dieter to play a match. In response, Dieter expressed that he would never want to play such a game because he cherished life's simple pleasures and the people he knew too much to risk losing it all in an instant.
Martin nearly fell off the roof afterward, but Dieter saved him. This incident made Martin realize that he didn't want to die either and decided to stop playing the "game."
