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.

Mechanics
In Kingdom Hearts 3D: Dream Drop Distance, Nightmare's End and Mirage Split are Reality Shifts for The World That Never Was. 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, Sora and Riku will swing the summoned Keyblade to cut apart obstacles or inflict damage to any nearby enemies.

Nightmare's End is also used by Sora to cleave the white-striped skyscrapers that block his path and fall from the sky, as well as to destroy the skyscrapers that Xemnas throws while also stunning him.

Mirage Split is also used by Riku to disable the nodes that were generating barriers throughout the Castle That Never Was, to stun and damage Ansem and create flat ground within his summoned arena, to damage and make Ansem unable to attack for a certain time in his second battle when Riku does lots of damage in a short time, and to directly attack Young Xehanort's time-controlling ability.