When does a Combat occur in Riftbound?

In Riftbound, a Combat occurs as part of the game's flow during specific phases, and one of the key moments is during the Cleanup phase when there is an empty Chain. This phase is essential as it indicates the end of a turn or phase, where players resolve damage, clean up any lingering effects, and prepare for the next turn. When the Chain is empty, it signals that there are no current actions or interactions occurring, thus allowing for Combat to be resolved as players strategically plan their next moves based on the game state.

The other options describe various elements of gameplay but do not accurately define when a Combat occurs. Declaring attackers is a part of initiating combat but does not signify the occurrence of combat itself, as the structure of the game sees combat resolved at specific phases. Calling for Combat as a player is not a mechanic recognized in the structured flow of the game, and instead, it is inherently tied to the game’s phases. A specific ability triggering might lead to interactions or effects but does not determine the occurrence of Combat in the mechanics of Riftbound.