This specific Jedi held the rank of Jedi Master and was a member of the Jedi Order during its concluding years. Kento Marek, his apprentice, survived him for a number of years after the Jedi's demise during the Great Jedi Purge.
As was typical for Jedi of that time, this individual commenced training with the Jedi Order in early childhood. After studying at the Jedi Temple located on Coruscant, this Jedi ultimately completed the Jedi Trials and was knighted by the Jedi High Council. Further study of the Force and refinement of lightsaber combat skills led to this individual being granted the title of Master. It was at this stage in their life that this individual noticed initiate Kento Marek and chose him to be their Padawan.
Having trained Marek to the rank of Knight, this Jedi Master became a general in the Grand Army of the Republic, fighting against the Separatist Droid Army throughout the Clone Wars. In 19 BBY, after Order 66 was carried out and the Galactic Republic fell, this Jedi Master was pursued and killed by the Dark Lord of the Sith, Darth Vader.
Upon hearing about his former master's passing, Marek and his Jedi wife, Mallie, escaped to Kashyyyk and went into hiding along with their son, Galen. Remaining loyal to their beliefs, the pair tried to help the local Wookiees fight off the Imperial invasion following the Galactic Empire's initial campaigns to enslave the planet. Before long, Mallie Marek died in combat, and eventually in 18 BBY Kento Marek met the same end as his master.
When Vader tracked down Kento Marek, he sensed a presence that was much stronger than Kento's nearby. Thinking it was Marek's master, Vader demanded to know where he was. Marek responded that the dark side had kept him from realizing that he had already killed his master years prior. Vader then stated that Marek would share the same fate.