This one sneaks up on you, because it opens as a comfort watch and then quietly asks what a lion is even for. Tezuka's Leo gets rebooted into the 21st century as a cub born inside "Eternal Earth," a corporate-built neo-jungle the UN signed off on after humans wrecked the real one, and the horror isn't cruelty, it's convenience. Every animal is safe, fed, managed, and Leo grows up breezy and useless because nothing in a nature preserve ever requires courage. Hanging Panja's name over him is the cruelest touch: a son measured against a father who lived when the wild was actually wild. It's a single special, so it moves like a fable rather than an arc, and it lands the way old Tezuka always did, by making the sweet thing hurt. Bravery you never had to learn is the sharpest thing here.
Leo grows up in an artificial jungle built by a corporation to preserve wildlife in a dying world. Born into legend as the son of the legendary Jungle Emperor, he carries expectations he can't live up to. The other animals see him as weak, a disappointment compared to his father's strength and leadership. Leo wants to prove himself, to become worthy of his name. When Kenichi arrives, the privileged human son of the company's CEO, he sees the neo-jungle as a triumph of technology and conservation. But his presence forces Leo to confront an uncomfortable truth: their sanctuary isn't nature at all. It's a cage made by the same forces destroying the world outside. As Leo and Kenichi's worlds collide, Leo discovers that proving his courage means facing a larger question. Can he change what's broken about this artificial world, or is he trapped by the very systems designed to protect him? His journey becomes less about living up to his father's legacy and more about deciding what kind of leader he wants to be.