Master Nekomamushi is a feline mink and the guardian of the Whale Forest on Zou, known as the "Ruler of Night." He governs the Mokomo Dukedom during nighttime, from 6:00 PM to 6:00 AM. Alongside Duke Inuarashi, Nekomamushi is one of the rulers of the Mokomo Dukedom, proudly declaring it his own when night falls, as he did during his first encounter with Jack.
In contrast to his former friend Inuarashi, Nekomamushi is aggressive and merciless. Inuarashi has described him as an "obstinate and stubborn imbecile," comparing him to Jack himself. Even when not angry, Nekomamushi can be stubborn, such as when he ignored Chopper's orders to rest so he could continue having fun. He dislikes being ordered around, stating that he went to bed on his own accord rather than following Chopper's instructions, and considers himself a "freedom-loving man." Despite his tough exterior, he is afraid of needles.
When the Heart Pirates, including Bepo, arrived on Zou, Nekomamushi took care of them, showing a welcoming side. He does not expect guests to help defend Zou, but he does not tolerate intruders, going so far as to devour them if necessary.
Like a cat, he enjoys licking his paws, playing with balls and cat toys, and eating catnip. Unusually for a cat, he loves taking baths. His favorite food is lasagne.
