Di-Kadi Sundi

Di-Kadi Sundi was a Jedi whose dodgy footwork led to his lightsaber being confiscated. He instead worked to perfect the Battle Meditation technique, which would aid his allies in battle. He taught this to one of his pupils, Bastila, which is why she was so important in the Rise of Trask Ulgo. However, by Guy from KOTOR 2's time, everyone knew Battle Meditation.

Di-Kadi was killed by Darth Malak during the Sith War, but an essence of his spirit survived in one of the Jedi Holocrons. Centuries later, he was resurrected, retaining none of his memories or dodgy saber skills and renaming himself Ki-Adi Mundi.