Kim Fulis (Jay's father) left Whale Island at the age of 12. At that time, there were only two children of the same age on the island, Kim and Mitt, who were three years apart. Twenty years later, Kim came back with Jay, who was still a baby, saying that he had separated from Jay's mother, asked Mitt to help with the children, and then left.
Shortly after Kim 12 left, Mitt's parents died in a car accident, and Kim's father later died at sea. Then my mother-in-law said, "As a result, both my sons died."
This means that Kim and Mitt are actually cousins. So it is wrong for some people to think that Jay's mother's sister is Mitt's sister. According to the experience gained from watching cartoons at ordinary times, in fact, Japanese women can be called "sang" as long as they are older. Sang is not menstruation, but also menstruation. Mitt and Jay's mother are not related by blood.
At present, there is no exact information about Jay's mother, so we have to wait for Togashi Yoshihiro to fill this loophole. Of course, it is also possible that Togashi Yoshihiro just forgot about it, and Jay's mother will always be a mystery.