When Shenron gave up his body for his mother's freedom, Kairo wished to see how other bodies reacted to Death God Chakra. Kairo thus used Shenron, whose soul is intertwined with a shinigami's, that naturally produces Death God Chakra, to develop a new brand of cursed seals that would feed off the wielder's chakra while supplying them with Shenron's Shinigami chakra. As a result, those compatible with the cursed seals are also compatible with Shenron, allowing him to not only heal them but also allow him to impose his will on them.