Bound By Flame Help The Elf Sentinels is another side quest that can be triggered after you complete The Dead City main quest, if on your way towards the camp in Steppes of Caraldthas, you visit the north watchtower.
The north watchtower is one of the two towers you have liberated when you have played The Dead City quest and it is also one of the locations you will have to visit when you work on completing A Traitor In the Camp side-quest.
After you exit Upper Caraldthas, thus opening the blocked door that allows you to enter The Icy Library, follow the path south-east towards the camp and when you get near the watchtower, the sentinel will inform you that the other watchtower was conquered by the enemies.
Additionally, you will be informed that the Deadwalkers set up a blockade, west from the watchtower.
Bound By Flame Walkthrough Help The Elf Sentinels Quest
Tip: Take Sybil with you for this quest and order her to heal both of you.
Once you activate the quest, first travel south to the tower and focus on killing the archers because they will slow down your hero.
Tip: The archer near the crates can be attacked from behind, while in ranger stealth mode.
When both archers are defeated you have to focus on killing the Spewer.
Tip: Remain in ranger stance and attack the Spewer. When you see the creature getting ready to strike, press B (on Xbox 360) to jump away, then attack again.
If the Spewer casts the cloud of poison and starts chasing you, place explosive traps on the ground.
Tip: The final attack should be ranged because the Spewer explodes, dealing increased damage.
Now, that you have killed all Deadwalkers near the tower, head west to deal with the blockade. Again, you will have to kill the archers first and then a Deadwalker wielding a purple sword which inflicts dark magic damage, draining your mana.
The said Deadwalker is very slow, and you can parry most of his attacks. Being an enemy vulnerable to fire attacks, cast Burning Weapon to increase the damage of your main weapon.
Parry and counter-attack to defeat the final Deadwalker and complete the quest.