The Four Black Mirrors are cosmic ships about 450 meters tall — “coffins on the grass” — that appear on the post-Triumvirate horizon of the new cosmos of the Supreme Ones.
| Type | Cosmic ships |
| Height | c. 450 m each |
| Setting | Post-Triumvirate cosmos |
| Spanish entry | Cuatro Espejos Negros |
Arrival
“They may only arrive in 500 years. Or they were arriving before.” For the Triumvirate, which is outside Time, both statements can hold at once; the Mirrors remain in temporal superposition until the new time, begun by the signature of the Unnameable, fixes their position. The Rod of Infinity of the closing opens the stage on which they appear.