Dark Impulse (KHBBS)

Dark Impulse is a Level 2 Command Style exclusive to Terra in Kingdom Hearts Birth by Sleep. It is activated by using Zero Gravity-related, Magnet-related,, or status-inflicting s, by using commands like Zantetsuken, Ars Solum, Limit Storm, Sacrifice, or Warp, or by using a Big Bad Pete.

Kingdom Hearts Birth by Sleep
After visiting Destiny Islands, Terra heads to the Badlands and talks to Master Xehanort. Xehanort tells him that Ventus is going to confront Master Eraqus about his past, and, fearing the worst, Terra goes after Ven.

Upon arriving at the Land of Departure, Terra defends Ven from Eraqus's light attack and refuses to budge in the face of his master's Keyblade assault. When Eraqus uses his light magic to knock the two boys back, Terra summons his darkness and sends Ventus into the Lanes Between. In the ensuing battle with Eraqus, Terra uses his darkness to amplify his attacks.

Mechanics
When using Dark Impulse, Terra gains a dark aura around him and a black light is focused on his left hand. Wisps of darkness emanate from his body as well. While using Dark Impulse, Terra's attacks become faster and deal dark damage. The standard four-hit combo lifts him off the ground as he barrages enemies with a fast and furious flurry of Keyblade slashes and clawing attacks from the free hand. The combo finisher ends with Terra materializing a large hand of dark energy. The Dark Impulse finish command has Terra sink into the ground, move underneath an enemy, and burst out of the ground performing an uppercut with the large hand.

Kingdom Hearts Birth by Sleep

 * Terra learns Dark Impulse after visiting the Keyblade Graveyard a second time.

Kingdom Hearts Birth by Sleep
Terra-Xehanort can perform Dark Impulse in his battles against Lingering Will and Aqua. His version of the attack consists of Terra's four-hit combo, following up the combo finisher with the Finish command.