Khotun Khan is not a simple conqueror. He is a strategist who understood before the invasion that Tsushima's greatest vulnerability was its code — that an enemy who fought without rules had an automatic advantage against an enemy who refused to fight without them. The storm he sent was designed specifically for what Tsushima was.

Jin becoming its thunder means accepting the same asymmetry in reverse. The ghost is what happens when the defending force abandons the constraints the invader was counting on. The Khan planned for samurai. What he got was something the island invented in response to him, shaped by exactly the storm he created.