Master Nekomamushi is a feline mink and the guardian of the Whale Forest on Zou, dubbed the "Ruler of Night." He rules over the Mokomo Dukedom during the night hours, from 6:00 PM to 6:00 AM.
Nekomamushi is the other ruler of the Mokomo Dukedom, alongside Duke Inuarashi, and takes great pride in it by proclaiming the country to be his when the night comes during his first encounter with Jack.
Unlike his former friend Inuarashi, Nekomamushi is aggressive and merciless. Inuarashi has described him as an "obstinate and stubborn imbecile," comparing him to Jack himself. Nekomamushi can be stubborn even when not angry, as he kept ignoring Chopper's orders to recuperate in order to have fun. He does not like to be ordered around, as shown when he stated that he went to bed of his own volition rather than on Chopper's orders, and describes himself as a "freedom-loving man." Despite his bravado, he is shown to be afraid of needles.
He took care of Bepo and the other Heart Pirates when they arrived on Zou, indicating a welcoming personality.. He does not expect guests to help him defend Zou. However, he does not look kindly upon intruders, going so far as to devour them if he ever sees one.
Just like a cat, he likes to lick his paws, play with balls and cat toys, and eat catnip. Unlike most cats, however, he loves taking baths. His favourite food is lasagne
