You and every other Fereldan in this dump. Find another meal ticket.
~ Bartrand Tethras to Hawke

Bartrand Tethras is a dwarven rogue and a hidden antagonist in Dragon Age II, though he begins as a somewhat gruff yet seemingly well-meaning figure whose betrayal does not take place until later in the game. He is Varric's older brother. He was voiced by Keith Szarabajka.

After gathering a party to explore the dangers of the Deep Roads with the aid of Hawke and Varric his own brother, Bartrand aids the Party and begrudgingly offers an even trade - waiting until they found an ancient artifact made from an exotic type of lyrium.

However, upon getting his hands on the artifact and being exposed to the lyrium Bartrand's inner-greed was exposed and he lost his sanity - heartlessly locking his brother and the rest of the group inside the Deep Roads with the intent of letting them die, stating that he had no desire to share the wealth with any of them.

If Carver or Bethany (depending on Hawke's weapon class) are present, then they can be made Grey Wardens and survive if Anders is present as well. If Anders is not present, then they will sacrifice themselves and die. If Hawke doesn't take them in the expedition, then Bethany will be captured by the Circle of Magi and Carver will join the Templars.

Although the group do escape (and gain considerably valuable treasure and wealth as a result) Bartrand manages to evade justice for three years - during which tales spread of his growing insanity as a result of the cursed artifact: torturing his bodyguards and servants by forcing them to eat lyrium while he mutilated them and went on about dance and song. If Hawke and Varric investigate this in his personal quest Family Matter, then they will discover corpses everywhere in Bartrand's mansion, in addition to crazy bodyguards. There will be an interrogation cutscene between Varric and Cassandra Pentaghast, where Cassandra will doubt that Varric took out everyone by himself. In addition, a dwarf named Hugin, the only survivor of Bartand's mansion, will tell Hawke and Varric that after Bartrand's betrayal in the Deep Roads, Bartrand started hearing voices, claiming that the lyrium idol was "singing" to him. Even after selling it, Bartrand could still hear the idol and was driven mad by it. He tortured his servants by cutting pieces off them to help them "hear the song" and fed his guards lyrium, which drove them insane. Hugin then strongly suggested they kill Bartrand and advised the group to proceed with extreme caution.

Varric seeks to kill his now insane brother, if Anders is present in the Party, he can temporarily restore Bartrand's sanity, if he does this then Bartrand expresses remorse for his actions and begs Varric not to leave him like this and not to allow House Tethras to meet such an undignified end. His ultimate fate is then decided by the player - if he is spared he is left at his estate temporarily before being sent to a sanitarium, but if the choice is made to kill him, then Varric will do it via shooting him with a crossbow bolt.

Depending on whether or not Bartrand was healed will affect Varric's approval rating towards Hawke: If Anders heals Bartrand, then Varric will approve if Hawke lets him go, but he will disapprove if Hawke has Varric kill him. If not, then Varric will approve for killing him and disapprove for letting him go. If Aveline however, is present, she will always approve for killing Bartand, and disapprove for letting him go. Sebastian however, will always approve for letting Bartand go and disapprove for killing him. Everyone else's approval ratings will not be affected regardless what choice is made.

The artifact however is not to be found as Bartrand had already sold it to a woman (though in his madness he lost sense of logic, so he claimed she stole it).