Game:Xion

Strategy
When it comes to fighting Xion as a boss, things get a lot more complicated. In an attempt to absorb Roxas and become whole, Xion transforms into an armored monster, resulting in a series of cinematic battles. Each battle also represents one of Sora's drive forms from Kingdom Hearts II, a connection that they are the same being.

First Form
The first battle against Xion takes place in the Bizzare Room, and it is easiest. The winged Sora copy mainly glides around the battlefield, sometimes performing a melee attack, knocking opponents out of the way in a burst of energy, or diving at Roxas from the air. (This relates to Sora's Valor Form).

Second Form
The second battle takes place in Halloween Town, the now grounded Xion opening vortexes the pull the Key of Destiny in for an attack, slashing Roxas with an ax, or shooting beams of energy. This relates to Sora's Master Form).

Third Form
The third battle takes place in Agrabah, specifically in the Cave of Wonders. The grounded Xion opens vortexes, dives from the air, shoots lasers, or rapidly slices Roxas with her four swords. This form of Xion resembles Kurt Zisa from Kingdom Hearts Final Mix, but it is white in coloration. It demonstrates just as much grace and agility as the previous forms, making attacks hard to land. (This form relates to Sora's Wisdom Form).

Final Form
The final, cinematic battle with Xion takes place outside of the Train Station in Twilight Town. The now giant Xion shoots lasers, unleashes shockwaves, performs melee attacks, and performs a powerful desperation attack combining shockwaves and bursts of energy. Another desperation attack is when Xion also uses vortexes to suck Roxas in the center of the field and creates a circular outline that surrounds almost the whole field; being inside the circle will deal massive damage to Roxas. To avoid this attack glide on the edges of the field and keep gliding until the attack is finished. All of these attacks have great power, so Roxas' Limit Break is highly recommended. Using the Limit Break will almost always ensure victory, also quickly depleting the Sora copy's multiple HP Bars. (this relates to Sora's Final Form).

Trivia

 * It is completely unknown why Xion chooses Wonderland as one of her boss battle worlds.
 * The armor worn by Xion during her various Boss Battles is said to mirror the clothing of either Roxas or Sora in Kingdom Hearts II.