Twins -- Juvenile fiction. Brothers and sisters -- Juvenile fiction. Kings and rulers -- Assassination -- Juvenile fiction. Kings and rulers -- Succession -- Juvenile fiction. Competition -- Juvenile fiction.

Genetic engineering -- Juvenile fiction. Extraterrestrial beings -- Juvenile fiction. Contests -- Juvenile fiction. Science fiction. Young adult fiction.

Survival -- Fiction. Television programs -- Fiction. Interpersonal relations -- Fiction. Contests -- Fiction. Science fiction.