(陸奥 Mutsu), Seiyū - Akeno Watanabe

Mutsu is Sakamoto's first mate on his business fleet. She has a no-nonsense attitude, and appears to be the person actually running Sakamoto's business, since he is prone to seasickness, and in any case, he is often off gadding somewhere. While Mutsu disapproves of Sakamoto's frequent misadventures, she always helps him out of trouble.

Her name is based on Mutsu Munemitsu.

Source: Wikipedia