Location from enders-game by Orson Scott Card
The facility inside an asteroid where Ender fought 'simulations' that were actually real battles — the place where a child committed xenocide without knowing it.
Command School exists inside Eros — a spindle-shaped asteroid that the Formics carved out during the Second Invasion. The tunnels are designed for Formic proportions (low ceilings, smooth walls), making humans feel perpetually uncomfortable. About 500 people live here. Ender arrived at age 10 — typical entry age is 16. Mazer Rackham trained him through increasingly difficult 'simulations' that were actually real-time fleet combat transmitted via Ansible. Ender's jeesh — his sub-commanders from Battle School — managed fleet sections. When Ender deployed the MD Device against the Formic homeworld in what he thought was his 'final exam,' he destroyed a planet and an entire species. The reveal that the simulations were real is the most famous twist in science fiction.
Inside the asteroid Eros — labyrinthine tunnels with low ceilings carved by the Formics during the Second Invasion. Cold, metallic, claustrophobic. The simulator room where Ender commanded fleets is the most significant room in the Enderverse.
Also known as: Command School, Eros