Master Xehanort (RoTs)

Master Xehanort, also known as the Original Xehanort, was the wielder of a powerful Linchpin Keyblade back during the days of the Keyblade Wars. He is mentioned in legends throughout the Road of Twilight series.

Master Xehanort was believed to be a student of the original creators of the Linchpin and normal Keyblades: Tenno and Mahikari, despite being the master of the Linchpin Keyblade called the η-Blade he wanted to gain access to the χ-blade, although he failed he managed to form a cult obsessed with fusing his Darkness and Kingdom Hearts together which seek out his reincarnation even today.

Master Xehanort is currently succeeded by his modern day successor, Xehanort, who is his reincarnation.

Trivia

 * Similar to in "Birth By Sleep", Master Xehanort seems to be the cause of the Villains' goals to gain Kingdom Hearts.