Mr. Duffi is the mine boss and a highly respected leader among the townspeople. Although he is Pazu's boss, Mr. Duffi also watches out for the orphaned boy, as does his wife Okami. When Pazu befriends Sheeta, Mr. Duffi protects her as well and stands up to the air pirates on her behalf.

Mr. Duffi is rightfully proud of his incredible strength. When facing off with the pirates, he and Louis compete to see who is stronger. Louis flexes his chest and arm muscles until his shirt rips to pieces. However, Mr. Duffi is even stronger than Louis, and when he flexes, he is bigger and shreds his shirt even more.

(Source: Studio Ghibli Wikia)