Kekkei genkai are a little like your mutations. There's a quirk in a person's DNA that allows them certain abilities, usually to do with chakra. They're passed down parent to child and so clans with them tend to be known for them.
But after there was a period of time where people weren't too big on them--they were scared of the power it granted the user. So they killed people who were born with them. It didn't happen everywhere, but it happened enough in certain places that it was notable.
[filtered]
But after there was a period of time where people weren't too big on them--they were scared of the power it granted the user. So they killed people who were born with them. It didn't happen everywhere, but it happened enough in certain places that it was notable.