Who is the final boss of Kingdom Hearts II?

The final boss of Kingdom Hearts II is Xemnas. As the leader of Organization XIII, he is the game's main antagonist and the final enemy Sora and Riku face.

Xemnas is the Nobody created when Xehanort separated himself from his heart. He uses the identity of Ansem, the former master of Radiant Garden, and directs Organization XIII's efforts to construct an artificial Kingdom Hearts. His plan is to gather enormous power and ultimately use the organization's members as vessels for Xehanort.

The ending battle is a multi-stage confrontation at The World That Never Was. Xemnas first fights Sora, later takes a massive Dragon-like form, and then battles Sora and Riku together. The final phase includes Xemnas's attempt to attack them with a barrage of energy blades. Players sometimes confuse him with Ansem, Seeker of Darkness, because both are forms created from Xehanort and both appear in the series' major climactic battles. In Kingdom Hearts II, however, Xemnas is the final boss.