Apocalypse Daycare: My Zombie Toddlers

SS level zombies can speak human language, speak normally, and have no difference in intelligence compared to normal people. S-level zombies awaken some spiritual intelligence, but cannot speak. All zombies have underlying logic, and their state is not good. They need to transform into humans. And the male lead can make the children more intelligent, closer to humans, and stronger at the same time. The male protagonist is unaware that his first group of students were already the youngest SS level zombies in the zombie world.