Nightmare's End and Mirage Split

Nightmare's End (ナイトメアブレイク) and Mirage Split (ミラージュスプリット) are twinned techniques which appear in Kingdom Hearts 3D: Dream Drop Distance. They allow Sora and Riku to meet from across their separate dream worlds and each summon half of an enormous, filigreed Keyblade, which they combine to perform several powerful slashes. Nightmare's End and Mirage Split are Reality Shifts for The World That Never Was.

Mechanics
In Kingdom Hearts 3D: Dream Drop Distance, once the Reality Shift is started, several cycling chains appear on the touch screen. The player must use the stylus to cut through each chain's weak link with three cuts or less. Once Nightmare's End or Mirage Split is activated, the Combined Keyblade appears and Sora and Riku proceed to cleave apart nearby enemies or obstacles. In particular, Nightmare's End is used to destroy the skyscrapers that block Sora's way and regularly fall from the sky in the Dark City, while Mirage Split is used to deactivate the nodes producing barriers throughout the Castle That Never Was. Both Reality Shifts also produce special effects during the Xemnas, Ansem, and Young Xehanort boss battles.

In Kingdom Hearts Dream Drop Distance HD, one half of the Combined Keyblade appears on the screen, with a line showing where it will cut. The player can move the Keyblade up and down with and press  to cut.

Kingdom Hearts 3D: Dream Drop Distance

 * Sora can use Nightmare's End when a Reality Shift is triggered in The World That Never Was.
 * Riku can use Mirage Split when a Reality Shift is triggered in The World That Never Was.

Kingdom Hearts III
When Sora joins Riku in the Realm of Darkness, they summon the Combined Keyblade to defeat the Demon Tower.