Real kids pick the manga. An adult signs off on every one.
Most subscription boxes are filled by an algorithm or a warehouse. Cardinea is filled by two kids who actually read this stuff, for readers their own age, with an adult reviewing every pick for age fit before it ships. That is the whole idea.
Iris
Reads ages 8 to 12
Iris reads for the eight to twelve crowd. She loves a world she can live in, a friendship at the centre, and a story that is kind even when it is exciting.
Meet Iris
Keane
Reads ages 12 to 15
Keane reads for the twelve to fifteen crowd. He goes deep on long running series, likes a hero who earns it, and can tell you the exact chapter a story got good.
Meet KeaneHow the adult review works
Nothing mature is in the catalog to begin with, so it can never end up in a box by accident. On top of that, an adult reviews every pick against the reader's age band before it ships, and every box includes a parent card that spells out the age rating, the themes, and what to expect. Kids choose the books. An adult signs off on the fit.