Vanitas

Vanitas (ヴァニタス, Vanitasu?)[54] was the embodiment of the darkness in Ventus's heart, created by Master Xehanort. His name Vanitas means "emptiness" in Latin, but also suggests "vanity". As a result, while Ventus resembles Roxas, Vanitas bears a likeness to Sora with golden yellow eyes and black hair. He originally wields a Keyblade simliar to that of Riku's Soul Eater, using a similar fighting stance and armour nearly identical to Riku's Dark Form. He monitors Ven's strength and progress in the hopes of absorbing his power prior to obtaining the Χ-Blade, a powerful Keyblade that can unlock Kingdom Hearts. By the end of the game, after being defeated within Ven's subconscious, Vanitas is destroyed and the Χ-Blade is shattered by Aqua in the physical realm. Ven's body is rendered dead while his incomplete organs enters a young Sora. He is voiced by Miyu Irino in the Japanese version of the game.

A secret boss in the game known as the Vanitas Sentiment appears after completing the final episode. It bears an appearance almost identical to Vanitas, only black and white, and the Unversed emblem on the helmet. It's moveset is a more powerful version of the original Vanitas. Any connection between Vanitas and the Vanitas Sentiment is currently unknown.