Defeat Mephiles

They are in Acmetropolis

Ace: Is this... Is this my home?

They went to the Secret Place

Mephiles: This world has been connected.

They saw the City disappeared

Wile: What was that?!

Mephiles: Tied to the darkness... Soon to be completely eclipsed, There is so very much to learn, You understand so little, A meaningless effort, One who knows nothing can understand nothing.

They saw Mephiles as Duck

Mephiles: Take a look at this tiny place, To the heart seeking freedom this city is a prison surrounded by water. And so this boy sought out to escape from his prison, He sought a way to cross over into other worlds. And he opened his heart to darkness.

Duck has turned into Mephiles

Ace: Duck!

Ansem: Don’t bother. Your voice can no longer reach him where he is. His heart belongs again to darkness. All worlds begin in darkness, and all so end. The heart is no different, Darkness sprouts within it, it grows, consumes it. Such is its nature. In the end, every heart returns to the darkness whence it came.

(They hear his voice behind them and whirl around as he speaks, having teleported. Tino jumps back)

Ansem:  You see, darkness is the heart’s true essence.

Tino Tonitini: That’s not true! The heart may be weak. And sometimes it may even give in. But I’ve learned that deep down, there’s a light that never goes out!

(Ansem rises into the air, crossing his arms. He stares down at them through piercing orange eyes)

Mephiles: So, you have come this far and still you understand nothing. Every light must fade, every heart return to darkness!