Asunder

In Asunder, you piece together the three parts of a pride demon. You then can kill the beast or set it free for a reward.

Start Condition: Opening a small bloody sack found in the Deep Roads

Progressing the Quest: The bag of limbs is in the first darkspawn clearing in Aeducan Thaig, the torso in a bag in the southeast cavern of Caridin’s Cross, and the head in the deepstalker clearing in Caridin’s Cross. Once you have all three components, seek out the Altar of Sundering in Ortan Thaig and place the three bloody items on the altar.

Completing the Quest: The pride demon will appear, and is willing to reason for you. If the player character fights it, they may be rewarded with a breastplate or frost sword, or possibily  nothing. If the PC allows it to leave, the demon will reward them with 25 gold, though others will ultimately suffer for the PC's greed.

Reference
PRIMA Offical Strategy Guide