Jinmenjuushin

Jinmenjuushin(人面獣心, Beast in human form) are a special breed of people that are extremely rare in the world. They occur when a summoner of a certain animal allows one of the animals give up their lives and fuse their chakra with the unborn baby. It is sort of like sealing however the baby is half human half beast. This normally won't make their physical body change much however they do gain certain traits and features, some can even transform into the beast. For example a human/turtle may gain hardened skin or a human/dog may gain a better sense of smell.