This hat also has an "entity" that can control the body of Mario.
Mario is mysterious boy who bears the second penguin hat; and the younger brother of Masako. He is a sickly boy that requires the penguin hat to live, like Himari. He is also next in line to lead the clan, being the only male heir.
Masako is Mario's older sister. She cares a lot for him, even if it means to eat the poisonous blow fish to free his grandfather's posession within him. And is trying to obtain Ringo Oginome's diary to free him from his illness.
Like Masako, Mario also is a true biological sibling of Kanba, although the two are not seen in any direct interactions due to Mario's young age upon their seperation.