Ars Solum

Ars Solum (ソロアルカナム) is a technique introduced in Kingdom Hearts Birth by Sleep. The user assails enemies with a ferocious multi-hit combo that leaves petals of darkness in its wake, and can add three additional hits by pressing successfully when the on-screen prompts appear.

Mechanics
In Kingdom Hearts Birth by Sleep, Ars Solum is an Ultimate exclusive to Terra. It takes up two slots, has a maximum level of 6, a normal reload time of 25 seconds, and fills the Command Gauge by 6% per hit.

In Kingdom Hearts Union χ, Ars Solum is a special attack that targets all enemies. It costs 2 special attack gauges to perform. It deals extremely powerful hits, and raises the Player's Magic-based strength by 2 tiers for 1 turn.

Ars Solum II (ソロアルカナム2) is a special attack that targets all enemies. It costs 3 special attack gauges to perform. It increases the Player's Special Attack Bonus by 30% for 1 turn. It inflicts more damage with 1 enemy left (including raid boss parts).

Kingdom Hearts Birth by Sleep

 * Terra can create Ars Solum through Command Melding.
 * Terra can acquire this Attack command from a chest found in the Skull Rock Cavern.

Kingdom Hearts Union χ

 * Ars Solum +5 is the special attack for medal.
 * Ars Solum II +5 is the special attack for medal.

Kingdom Hearts Birth by Sleep
Ars Solum is a Ultimate-class Attack Command that can be melded through seven different recipes, listed in the Giga Attack Recipe.
 * The first recipe can only be melded by Terra, and is a recipe that has a 5% chance of transforming from Thunder Surge.
 * Confusion Strike (LV3) + Thundara (LV3)
 * The second recipe can only be melded by Terra, and is a recipe that has a 20% chance of transforming from Chaos Blade.
 * Sonic Blade (LV5) + Dark Haze (LV4)
 * The third recipe can only be melded by Terra, and is a recipe that has a 20% chance of transforming from Zantetsuken.
 * Stopga (LV4) + Dark Haze (LV4)
 * The fourth recipe can only be melded by Terra, and is a recipe that has a 20% chance of transforming from Zantetsuken.
 * Stopga (LV4) + Sonic Blade (LV5)
 * The fifth recipe can only be melded by Terra, and is a recipe that has a 5% chance of transforming from Stun Edge.
 * Thundara (LV3) + Strike Raid (LV3)
 * The sixth recipe can only be melded by Terra, and is a recipe that has a 5% chance of transforming from Stun Edge.
 * Thunder (LV2) + Sliding Dash (LV2)
 * The seventh recipe can only be melded by Terra, and is a recipe that has a 5% chance of transforming from Stun Edge.
 * Thunder (LV2) + Strike Raid (LV2)

Other appearances
Terra-Xehanort inherits this technique from Terra, and uses it during his boss battle, though the speed of the three hit finisher is greatly increased through the power of darkness.

Etymology
"Ars Solum" is a pun on the ability's original name "Solo Arcanum" (roughly, "Only Secret" in Latin), and Last Arcanum's dub name of "Ars Arcanum" (roughly, "Secret Technique"). As such, it is meant to mean "First Technique". "Solum" can also be read as "ground" or "earth" in Latin, playing on Terra's own name; as such, "Ars Solum" can be read as "Earth Technique".