Multivortex (マルチボーテックス Maruchibōtekkusu ) is a technique exclusive to Ventus in Kingdom Hearts Birth by Sleep. The attack consists of teleporting and slicing the enemy with swift barrages of blades of energy.
In Kingdom Hearts Birth by Sleep, Multivortex is Ventus's ultimate Shotlock that has a maximum level of 6 and max lock of 30. Once the attack has begun, the player can perform extra attacks by rotating the analog stick in a complete circle several times to spin in the air to conjure up a gigantic whirlwind filled with stars that damages all the enemies in the area.
Kingdom Hearts Birth by Sleep
"Multivortex" is a classification of a type of tornado. Specifically, one that has multiple vortices revolving in and around the main funnel cloud. The name fits Ventus's wind theme.