Alfons Heiderich is a character exclusive to Fullmetal Alchemist the Movie: Conqueror of Shamballa which concluded the story of the 2003 anime series. He is a young German rocket scientist whom Edward Elric meets after being sent over to 1921 Munich. The two studied rocketry under Dr. Hermann Oberth in Romania, and when they returned to Munich, Heiderich let Ed board with him after Hohenheim's disappearance. Easygoing and kind-hearted, Alfons enjoys hearing Ed's stories about coming from another world, but doubts their truthfulness and is hurt by Ed's eagerness to leave and his assumption that this world and its people are just a waking dream.
Though Heiderich helps Ed shelter the Roma girl, Noah, from the Thule Society, he readily accepts Thule's offer to sponsor his research and projects, despite his disagreement with the racist concept of an "Aryan Race". Heiderich has a reason for wanting to complete his dream of proving his country's scientific worth as soon as possible, as he is succumbing to fatal lung disease.
Heiderich neither knows nor believes that Thule is planning to use his research projects to invade and plunder Ed's world - leading to an intense confrontation where he reveals his sickness- until he sees it for himself. After reminding Ed that he and this world are real and not just a dream, and asking that he not forget him, Heiderich then helps his reluctant friend return home by sending him back through the opened Gate in a two-seater rocket, but is soon gunned down by Rudolf Hess, who would later be one of Hitler's right-hand men in the Third Reich, only to steal a Luftwaffe plane intent on winning over Winston Churchill and crash-land in a field in Scotland.
When Ed decides to return to this world, he is shocked and saddened to find Heiderich's corpse cradled in Noah's arms. During Heiderich's funeral, the Elric brothers, Noah, Maes, and Gracia Hughes's counterparts, and others are seen there.
- By his name and appearance, it is obvious he is the real-world parallel counterpart of Alphonse Elric, Edward's brother. Unlike most counterparts, however, Alfons is differentiated from Alphonse in many ways, such as being much older, being ill with lung disease, as well as not sharing Alphonse's voice actors.
- It was hinted that Heiderich really is Alphonse's counterpart when it was mentioned that Alphonse had a dream that he was 17 years old with an illness, living with Ed, and making rockets dreaming to go to space.
- It is never said which illness Alfons was suffering from. However, given his symptoms, which consists of heavy coughing and later Hemoptysis (the symptom which has one coughing up blood), it is likely that he contracted a form of lung disease from breathing in rocket fumes and the air pollution the fumes caused, as well as the air pollution of the age. This is proven true as a fan-translated guidebook said that his illness was lung cancer, which was caused by the inhalation of rocket fumes.
- His English voice actor, Jason Liebrecht, also voices Karley in the 2009 anime series.