During the Belkan War, his actions made him known as "The Iron Man".
On May 12, 1995, Muller was deployed to Solis Ortus to engage Allied Forces in the area. He was later shot down by Galm Team. Despite receiving a severe wound to his midsection, he once again returned to the front lines a month later.
- His nickname "The Iron Man" is a direct reference to the comic book hero Iron Man.