Tetsu is a young boy living in the town of Rush Valley in southern Amestris. With his right leg replaced with an automail prosthesis due to an unknown accident, Tetsu relies on the Atelier Garfiel for his mechanical upkeep and repairs, specifically Atelier Garfiel's pretty new apprentice Winry Rockbell. During Winry's long absence in Central City, Tetsu is one of the clients who speaks to her over the phone, enthusiastically requesting her speedy return and he himself comments cheekily that he would prefer to have a pretty girl like Winry working on his leg than chief engineer Garfiel.
- Tetsu, 鉄, means "iron" in Japanese, possibly a reference to his automail leg.
- He makes a cameo in the Ending 3 from Fullmetal Alchemist: Brotherhood.