Keyblade Armor

Keyblade Armor (キーブレード鎧 Kīburēdo Yoroi) is a suit of armor worn by Keyblade wielders. It first appears in Kingdom Hearts II Final Mix, as the remnants of Terra and Aqua, and is used throughout Kingdom Hearts Birth by Sleep by Terra, Ventus, Aqua, and the digital simulations of Master Eraqus and Master Xehanort. One of its most important qualities is that it protects the wearer from the darkness surrounding the Lanes Between, much like the Black Coat. However, it is also worn during battle, at the user's discretion.

Pieces of the armor usually appear as part of the user's normal clothing, such as their boots or belts. However, the armor's left pauldron is more important—by pressing it, the user activates the rest of the armor, which appears in a flash of light. Despite the fact that it usually appears and disappears magically, the armor can also be removed physically, as Terra-Xehanort did once he had gained control of Terra's body, and Aqua did to give Terra's body a vessel to take him out of the Realm of Darkness. Despite its heavy appearance, the armor does not appear to impede movement in any way

Design and conception
In The Gathering and the Birth by sleep videos, the Armor worn by Terra, Aqua, and Ventus have capes. The capes were removed in Kingdom Hearts Birth by Sleep due to frame rate issues.

Nomura stated in an interview that he chose armor to hide Terra, Aqua and Ventus's faces so as to avoid using the black Organization XIII coats again