Ragnarok

Ragnarok(ラグナロク Ragunaroku) is a special ability present in Kingdom Hearts, Kingdom Hearts: Chain of Memories and Kingdom Hearts II: Final Mix+. In Kingdom Hearts, it is learned after Sora's second encounter with Riku, or after Riku is under the possession of Xehanort's Heartless, to be precise. However, it unaccessable once it is learned because Sora becomes a Heartless immediately after the battle. Sora can only access this ability once his Heart has been restored by Kairi and the subsequent series of events have transpired.

Kingdom Hearts
Ragnarok AP cost: 4 MP Cost: 3 Description: A flurry of air combos which ends with a laser burst. Deals Light-elemental based magic damage. Effect: When close to an airborne enemy, Sora will automatically jump up to the enemy and deliver a series of mid-air slashes. Unlike Sonic Blade or Ars Arcanum, it requires no timing to execute the finisher, Burst; however, it should be noted, the longer Sora charges for the Burst attack on air, the heavier the damage inflicts. Aside from that, the lasers fired also have homing capabilities, which target and destroy the nearest foes in sight. Sora can move freely while the lasers home by themselves.

Kingdom Hearts: Chain of Memories
It reappears in Chain of Memories, but this time as a Sleight. It also is a sleight in Kingdom Hearts Re:Chain of Memories. In Chain of Memories, you learn it at Level 47. In Re:Chain of Memories, you learn it at Level 52 To use it, stock the card and press A or. Press A or to fire sooner, but less rays are fired.

This is the Attack Card requirements for Ragnarok:

Kingdom Hearts 358/2 Days
When Roxas fights Xion's 2nd form, she seems to be using an improved Ragnarok, with homing beams of light that chase after Roxas.

It is also seen in Mission Mode as Sora's limit, where he fires off multiple Ragnarok blasts.

Kingdom Hearts II: Final Mix+
Ragnarok makes a comeback as one of four of Sora's former abilities to appear as one of Sora's Limits while Limit Form is equipped. Activating Ragnarok will trigger a Reaction Command, Burst, and just as in the first game, has to be hit at the right time for more projectiles to be fired. Hitting too early will cause fewer lasers to be fired.