Dav Kylanu was a Jedi Master during the final days of the Old Republic and fought in the Clone Wars. He took the young boy, Antinnis Tremayne as his Padawan whom he trained up through the war. Kylanu was always concerned with the boy's obsession with vanity and appearance, and many times did Kylanu admonish him for focusing on such things. Sadly, Dav was eventually killed in the war by the Confederacy of Independent Systems, and Tremayne's capture soon followed.
The boy was held prisoner until the end of the war, and his susceptibility to the Dark Side was exploited as he was hand-picked by Darth Vader himself to be one of the first students to be trained as one of the Empire's many Imperial Inquisitors. Jedi Master Dav Kylanu would certainly have been devastated by the fact that Tremayne forswore his Jedi oath to serve the evil of the Sith.