Avernus

"The Chantry foolishly forbids blood magic—but there are so many secrets to uncover."

Avernus is a Grey Warden that has lived since the time when Wardens inhabited Soldier's Peak also known as Warden's Keep.

Strategy
If the party did not kill Sophia and you side with Avernus against her, he will cast two fireballs on her, which will badly injure your party; he will then take you to seal the Veil immediately, so prepare potions to survive the fight.

Once the Veil is sealed, you can still choose to kill him, with no apparent negative result. The Warden may also choose to endorse his research and allow him to continue, or may command him to research only ethical ways to help the Wardens. Avernus says that he is near a breakthrough and will report any successes to you. No specific benefit or following quest has been reported.

Each time Avernus transits to a different map, you can Steal from him again.

Quotes

 * Avernus: Blood magic comes from demons; they could counter every bit of lore I possess. But the darkspawn taint, that is alien to them. And it has power.


 * Warden: "You practiced blood magic on the nobles?"
 * Avernus: "Of course. To nudge people, to keep our secret safe."


 * Warden: "I'm debating whether I should let you live."
 * Shale: "But the magus is a Warden, as well. Is he not an ally?"
 * Avernus: "Your golem is astute. You should be helping me, not issuing idle threats."


 * Leliana: "Careful, this... man has dabbled in matters forbidden by the Maker... he may look frail but don't trust him."
 * Avernus: "So the Maker told you that, did he? Short-sighted men have forbidden my research, not any god. Enough."