Spirit Island's invader phase is the part new players understand least well. The three-stage invader sequence — explore new land, build in explored land, ravage in built land — creates a predictable three-turn pipeline for invader development. A land being explored this turn will be built next turn and ravaged the turn after.

This predictability is the game's core planning tool. You can see exactly which lands will be ravaged two turns from now based on current exploration cards. Preventing damage in those lands requires either stopping the pipeline at the explore stage, blocking building, or having defensive presence in the ravaged land before it ravages.

For new Spirit Island players: spend your first two sessions tracing the invader pipeline explicitly. Name the lands that will be ravaged two turns from now. This single planning exercise transforms the game from a reactive crisis to a proactive defense.