Dimension Link

The Dimension Link, also known as D-Link, is a feature of summoning in Kingdom Hearts Birth by Sleep. Its name connects to its purpose as a link to summon a character's power from another world. The power originates from a spell Aqua puts on the Wayfinders she and her friends carry.

The player is also able to D-Link their friends while using their wireless functions. They appear as Terra, Aqua, and Ventus in their armor.

Usage
To use the D-Link (or Dimension Link) system, it must be added as a D-Link Command in its own separate D-Link menu and can only be used when the D-Link gauge is full. The D-Link gauge is blue and next to the HP meter. The D-link gauge is filled by obtaining dropped blue prizes from enemies similar to obtaining Drive Orbs to fill the Drive Gauge in Kingdom Hearts II.

Once characters have been linked, the Command Menu gauge, which is also used for Command Styles, changes to indicate the linked character, including his or her name, and the face of the linked companion will show up on the bottom right of the screen. By linking to them, the character that linked them will become more powerful and will also be able to use unique Finish moves which have two different power up levels: one for each symbol next to the character image on the right of the screen.

While linked, the D-Link gauge decreases continuously, and the link is broken when the gauge is completely empty, or when the player moves to another map or brings up the main menu.