Base of operations:
Otto is the blacksmith in Nottingham.
Cartoons: Robin Hood (1973)
Comics: Robin Hood (1973)
Country of origin:
Otto is one of the characters created for the Disney version of Robin Hood, and not a part of the original Robin Hood mythology. Like the rest of the cast, he first appeared in the cartoon Robin Hood
in 1973 (voice by J. Pat O'Malley), and like the rest of the cast, it has been the only appearance in cartoons so far.
In comics, he appeared with the rest of the cast in the comic book adaption of the cartoon from Gold Key in 1973, and appeared in the following series The Adventure of Robin Hood
which lasted seven issues from 1974 to 1976. After the series folded, only a few Robin Hood stories were made during the late 1970s and the 1980s, and in these, Otto only appeared a few times.
There are no indications of Otto having appeared in other media.