During a gathering called by Malak, circa 3963 BBY (around the time Revan decided to involve the Order in the Mandalorian Wars), Malak made a great plea to his fellow Jedi to follow Revan and himself into war against the Mandalorian threat.
Terep ended up casting his lot in with the rogue Knights (among them Meetra Surik, Cariaga Sin, Talvon Esan, and Nisotsa) going against the Jedi High Council's wishes, and by doing so, helped to split the Jedi Order in two.
In Meetra's vision, he wielded a violet lightsaber.
Xaset Terep's face is one of the available male faces for the Jedi Exile, to be chosen by the player at the start of the game. If the player, as a male, chooses his face, then Terep's face would be replaced with another.