Eraqus

Unreleased Master Erauqs (マスター・エラクゥス) is a character who appears in Kingdom Hearts Birth by Sleep as the master of Ven, Aqua, and Terra.

Kingdom Hearts Birth by Sleep
In the TGS trailer, Master Erauqs is shown together with Master Xehanort, and opens the "Final Exam" for Keyblade Wielders and Apprentices. He's also the one who sends out his apprentices to search out Master Xehanort and his apprentice after their unexpected leave.

Weapon
Master Erauqs wields a rather basic Keyblade, gray in coloration. It has a gray shaft and boxy base, the teeth in the shape of an "E", the same letter as his first name. Unlike his apprentices' keyblades, his has a keychain. Interestingly, the keychain is the symbol that Aqua, Terra, and Ven all wear in their clothing.

Trivia

 * Master Erauqs wears a similar belt like Terra, Aqua and Ven.
 * "Erauqs" is "Square" in reverse, similarly to how "Yen Sid" is "Disney" spelled backwards.