Blade of Mercy (Fenris)

Acquisition
The Blade of Mercy is a powerful greatsword that can be given to Fenris as a gift. It can be found during the quest Best Served Cold in Act 3.

When presented with the sword, Fenris tells you a history of the blade and how it's really a fake. Then he tells you about the history of the Tevinter Imperium, including slave labor, the magisters, and slave rebellions. At the end of the conversation you can choose to give the blade to Fenris or keep it. If you keep it, you get the Blade of Mercy. If you give it to Fenris he will get mad at you and tell you he wants nothing to do with the blade. Thus you get the blade either way.

If you have a high enough friendship, he will accept the blade. This sword seems to have a different appearance depending on what happens when you give it to Fenris as a gift. If he accepts the blade it will have the same appearance as his starting weapon, as well as being only able to be used by Fenris. If he rejects the blade or you choose to keep it, it will look like the Summer Sword.