Card Trivia:Caius the Shadow Monarch
- This is the cover card for The Dark Emperor Structure Deck and Structure Deck: Advent of the Emperor.
- This monster appears in the artwork of "By Order of the Emperor", "Red Screen", "Illusory Snatcher", "March of the Monarchs", "Domain of the True Monarchs" and "Tribute Carnival".
- In Roman history, the names Caius and Gaius are interchangeable. Therefore, this card's name is likely a reference to many powerful figures of the late Roman Republic, including Gaius Gracchus, Gaius Julius Caesar and Gaius Augustus.
- This is supported by the name of this monster's "Vassal" counterpart, "Lucius the Shadow Vassal", which is also a praenomen of Ancient Rome.
- This monster has an upgraded form: "Caius the Mega Monarch".
