Ars Arcanum

Ars Arcanum (ラストアルカナム) is an ability that appears in Kingdom Hearts, Kingdom Hearts Final Mix, Kingdom Hearts: Chain of Memories, Kingdom Hearts Re:Chain of Memories, Kingdom Hearts II Final Mix, Kingdom Hearts 358/2 Days, and Kingdom Hearts Birth by Sleep. It allows the user to attack enemies with a massive combo attack. In Kingdom Hearts and Kingdom Hearts Final Mix, it costs 4 AP to equip and 3 MP to use.

Kingdom Hearts and Kingdom Hearts Final Mix

 * Sora learns Ars Arcanum after defeating Captain Hook in Neverland.

Kingdom Hearts: Chain of Memories

 * Ars Arcanum is an Attack Sleight that Sora learns at level 37.
 * Its card combination is:

Kingdom Hearts Re:Chain of Memories

 * Ars Arcanum is an Attack Sleight that Sora learns at level 42.
 * Its card combination is:

Kingdom Hearts II Final Mix

 * Limit Form has Ars Arcanum as a default ability accessible from the Limit menu.

Kingdom Hearts Birth by Sleep

 * Ventus can create Ars Arcanum through Command Melding.

Kingdom Hearts Birth by Sleep
Ars Arcanum is an Ultimate-class Attack Command that can be melded through nine different recipes, listed in the Giga Attack Recipe.
 * The first recipe can be melded by Ventus, and is a recipe.
 * Aerial Slam (LV4) + Blitz (LV4)
 * The second recipe can be melded by Ventus, and is a recipe that has a 10% chance of transforming from Aerial Slam when Ventus melds it.
 * Aerora (LV3) + Fire Strike (LV3)
 * The third recipe can be melded by Ventus, and is a recipe that has a 5% chance of transforming from Slot Edge when Ventus melds it.
 * Cura (LV2) + Blizzard Edge (LV2)
 * The fourth recipe can be melded by Ventus, and is a recipe that has a 5% chance of transforming from Slot Edge when Ventus melds it.
 * Cura (LV2) + Poison Edge (LV2)
 * The fifth recipe can be melded by Ventus, and is a recipe that has a 5% chance of transforming from Blizzard Edge when Ventus melds it.
 * Quick Blitz (LV2) + Blizzara (LV2)
 * The sixth recipe can be melded by Ventus, and is a recipe that has a 5% chance of transforming from Blizzard Edge when Ventus melds it.
 * Quick Blitz (LV2) + Blizzard (LV2)
 * The seventh recipe can be melded by Ventus, and is a recipe that has a 10% chance of transforming from Blitz when Ventus melds it.
 * Quick Blitz (LV3) + Slot Edge (LV3)
 * The eighth recipe can be melded by Ventus, and is a recipe that has a 5% chance of transforming from Blizzard Edge when Ventus melds it.
 * Sliding Dash (LV2) + Blizzara (LV2)
 * The ninth recipe can be melded by Ventus, and is a recipe that has a 5% chance of transforming from Blizzard Edge when Ventus melds it.
 * Sliding Dash (LV2) + Blizzard (LV2)

Kingdom Hearts 358/2 Days
Although Ars Arcanum cannot be performed by any playable character, Xion can perform a modified version of Ars Arcanum in her third form.

Etymology
Ars Arcanum gets its name from the Latin ars meaning 'technique', 'skill' or 'art' and arcanum meaning 'secret'. It's Japanese name is "Last Arcanum", meaning "Last Secret".