Bound By Flame Save The Elf Soldiers is a side-quest that can be completed during the third act of the video game, but it must be discovered first.
However, it is a good idea to focus on Save The Elf Soldiers side-quest, after you regroup with Mathras, because you will be able to defeat your opponents faster having him by your side.
The following walkthrough refers to the side-quest named Save The Elf Soldiers available in Bound By Flame, and explains how to activate it, and how to complete it.
Bound By Flame Walkthrough Save The Elf Soldiers Quest
Before you can play Save The Elf Soldiers side-quest, you have to discover it. During your first visit outside Makeshift Camp, while trying to get to Blackfrosts Domain, as soon as you exit the camp you should see an area with two doors: one to the east, and one to the west.
Between the said doors, there is a third, at the bottom of some stairs, close to the southernmost point of your map. As you approach the door, you will hear someone asking for your help; however, if you try to open the door, you will notice that its locked.
Open your map, and head to the eastern door to enter Blackfrosts Domain. From there, cross the Great Square, moving west. Pay close attention to your map, and continue to head south and then east.
Tip: Your goal is to reach the central area which is protected by a General. Unfortunately, you wont be able to open the door unless you defeat the creatures protecting the area.
To defeat the General you should use the same tactics outlined in our walkthrough for Funeral March. After you deal with the General, open the door and stay alert because a Bone Golem just like the one you have encountered in The Lions Den will wait for you.
Kill the Bone Golem, then open the door and check the eastern room to find Buffalo and the western chamber to find several Elf guards. After you talk to Buffalo you will start The Blades Enslaved, and after you talk to the Elves you will finish Save The Elf Soldiers.
For this quest you will receive 3500 Experience Points and the Elite Soldiers Greaves.