Rules glossary
↑ Parent rule: 809.3 The Emperor variant uses the following default options.
809.3c A player can attack only an opponent seated immediately next to them, a planeswalker controlled by a player seated immediately next to them, or a battle protected by a player seated immediately next to them. Example: At the start of an Emperor game, neither emperor can attack any opponents, even though both of the opposing generals are within their spell range.
No sub-rules.