A male Jedi Master trained Jedi Winslau Da'k. The Master was imprisoned on Morcanth by his former student, as Da'k had been corrupted to the dark side of the Force by Darth Vader. Later, the Master was released and served his rescuers as a teacher in the ways of the Force.
A Force-sensitive, the man was trained in the ways of the Force by the Jedi Order and eventually attained the rank of Jedi Master. He trained the young initiate Winslau Da'k as his student.
At the conclusion of the Clone Wars, the implementation of Order 66 killed the majority of the Jedi and effectively disbanded the Jedi Order. Da'k and his Master survived, but at some point afterward, Da'k encountered Dark Lord of the Sith Darth Vader, who, despite the brevity of his contact with Da'k and unbeknownst to Da'k's Master, was able to corrupt the young Jedi to the dark side of the Force. The Jedi Master was surprised and overcome by his twisted student, who imprisoned him on the planet Morcanth, deep in the Unknown Regions. The power-mad Da'k incessantly assaulted him, attempting to attain mastery over his former master and gain knowledge before destroying him.
Weakened by these assaults and desperate, the Master used the last of his diminishing power to reach out across space for help. His pleas reached the minds of a group of Force-sensitive individuals who experienced visions and dreams of the man beckoning to them from his oppressive prison. The Master was also able to communicate the name of his prison world, Morcanth; however, Morcanth had been renamed on modern star-charts, and was thus a mystery to the group until they uncovered very old charts that used the original name. Upon journeying there, the group discovered the planet was located in disputed territory in a centuries-old war being waged by three local starfaring species, none of which recognized neutrality in their conflict. The group evaded the warring parties, neutralized Da'k's bevy of guards, and finally overcame Winslau Da'k himself, freeing the Master.
In gratitude, the Master offered to become an instructor and advisor for the Force-sensitive individuals who freed him from his prison. His tasks for the group led to them experiencing additional adventures, including at least two forays to Dantooine during Dorian passion fruit season to thwart alleged evil there.
The Master was an aging male. He enjoyed Dorian passion fruit, and at least one of his rescuers/students was suspicious regarding the timing of their missions to Dantooine consistently coinciding with passion fruit season.