An old reclusive automail master. His lifelong dream was to build automail with hidden cannons inside them, and he had the opportunity to do just that with Paninya’s automail legs. Winry begs him to let her be his apprentice, but he defers her to Garfiel instead, even though Winry helped deliver his grandson.
It is noteworthy that when he found out Winry was the granddaughter of Pinako Rockbell, he flipped out, as apparently he has some memories about the “Pantheress of Resembool” that he would rather forget (“Leopardess of Resembool” in the dubbed anime).
In the anime, no mention is made of any desire to build hidden cannons, though he did build one into Paninya’s right leg. He refuses to sell an automail arm to a young rich man because it is an arm for a fighter, and the young man does not really need it. At the end of the series, he is seen helping Winry train to become an even better mechanic.