EAST BRECILLIAN FOREST
Note: As the Warden progresses through the main quest, some of the wandering groups in this area will be repopulated. Keep your eyes open when backtracking.
As mentioned, the Warden can enter the East Brecilian Forest from the West Brecilian Forest via either of two passages. The Northern passage is guarded by a group of werewolves, while the Southern passage is guarded by one wild sylvan (best killed using ranged attacks as companions can get caught in traps surrounding it).
Note: Athras' wife, Danyla is found in the northern passage (East Brecilian Forest Map, L1), just past the werewolves. Lost to the Curse side quest will be listed under this East Brecilian Forest section.
A Landmark Tree lies just east of the campsite, up a short ramp. If Dog is in your party, you may use this to activate Mabari Dominance for this area.
The two Western paths converge at a central crossing, where you'll encounter three wild sylvans. From here, three paths leave in easterly directions:
North-East path (East Brecilian Forest Map, L2): leads to the Northern Ancient Tombstone;
East path: leads to the Mad Hermit (East Brecilian Forest Map, L3) Clearing
South-East path: leads to the Magical Barrier (East Brecilian Forest Map, L4)
The northeast and east paths are also connected after the respective landmarks. See below for more details on each section.
Note: A Skeleton between the South-East and East paths yields Mythal's Blessing and Codex entry: Mythal: the Great Protector.
The Magical Barrier
The southeast passage leads to a misty magical barrier: when the party tries to pass through, a cutscene shows them magically turned around, walking out of the mist in the same location where they entered it. The main quest line (Nature of the Beast) will be updated to reflect that the Warden needs to find a way to cross this barrier (placate the forest or trick it).
There are two main options to achieve this:
Side with the Mad Hermit found in the Eastern Forest: He will ask the Warden to kill The Grand Oak, and offers passage through the barrier in exchange.
Side with The Grand Oak found in the Western Forest: You will need to retrieve the Grand Oak Acorn from the Mad Hermit and the Oak will give the Warden an Oak Branch that allows passage through the barrier.
The Grand Oak
Mad Hermit
If you kill the Grand Oak first and don't have the wood, talk to the hermit, and he will offer to make you 'invisible' by enchanting a Werewolf Pelt, which you probably have since you picked it when killing them along the way. You also cannot kill the hermit (even with forced attack during dialogue with him) and will not find anything in the tree stump, i.e. cannot agitate him to attack you. As he 'teleports' away from your knife attack, Morrigan or Wynne will mention his use of illusions.
It is possible to kill both the hermit and the oak tree, by attacking the hermit and running away into the magical barrier and then going to the oak tree and killing the oak, then going back to the hermit who will still be hostile and killing him, but doing this will make it impossible to get past the magical barrier, also making the quest "Nature of the Beast" impossible to complete. You can also side with the Grand Oak by trading for the acorn, return the acorn to the Oak, and then come back to the Hermit and mess with his stump. This will cause the Hermit to attack.
For those playing on PC: With the latest patch for PC it is no longer possible to kill both the Mad Hermit and the Grand Oak using the method described above, because you can't leave the area while in Combat Mode, and you will stay in Combat Mode until the Hermit and his Allies are dead. Also, if you run to an Exit after having initiated Combat, the Hermit and his Allies will follow you, you cannot out-run them.
If you save before buying the acorn from the Mad Hermit, then buying it, go ahead and reload the save, then go to the Grand Oak. If you talk to the Oak, you will have the choice to give the Oak the acorn, though technically you haven't got it yet, and you can still keep the scarf for side quest.}}
If you have completed the Lost to the Curse side quest, you will no longer have the scarf, the hermit will trade for a shiny silver ring, when selecting from the found in the forest option.
Note: Once you pass through the barrier with either the Oak Branch or Magical Werewolf Pelt, the barrier disappears. Selling the staff and any leftover Werewolf Pelts does not impact venturing to the next area.
Northern Ancient Tombstone
The northeast path has several bears. Past them, the clearing in front of the ruins in this area is guarded by two ogres.
This is referred to as the Northern Ancient Tombstone since there are two landmarks in this section of the Forest marked as Ancient Tombstone on the map. The second one is found past the magical barrier, further south, and is referred to as the Southern Ancient Tombstone.
Among the piles of rubble and corpses in this clearing, there is a Gravestone, similar to the one found in the Western Brecilian Forest. Inspecting it, the Warden will find that "the air seems unnaturally cold around this ancient tombstone. Runes of warding are carved into the surface". If the Warden chooses to "Disturb the Wards", then The Mage's Treasure quest is added to the journal (if you didn't already start it), the Codex entry: Legend of the Juggernaut is unlocked, and the party will be attacked by a Revenant and his undead minions.
Once the Mage's Treasure quest is obtained, if the Warden has received the Thy Brother's Killer quest, and leaves the Eastern Brecilian Forest, a group of maleficar will spawn in the Northern Ancient Tombstone Clearing (towards the eastern-most path that leads to the Mad Hermit clearing).
On the path between the Northern Ancient Tombstone Clearing and the Mad Hermit Clearing, the Warden can find Aneirin, for the Wynne's Regret quest.
You can find a Steel Spiked Collar for Dog on one of the corpses.
The Mad Hermit
Southern Ancient Tombstone
On the other side of the Magic Barrier (East Brecilian Forest Map, L4), the Warden will encounter Swiftrunner once again. The dialogue may lead to more unanswered questions about the conflict between the Dalish elves and the werewolves, but will also lead to an unavoidable fight with Swiftrunner and 3 rabid werewolves. When Swiftrunner's health gets too low, Witherfang will make an appearance, and bring the fighting to an abrupt end, allowing Swiftrunner to flee. Just ahead lies the Southern Ancient Tombstone.
Note: Near the ruins (East Brecilian Forest Map, L5), the Warden will find a Pile of Rubble (yielding an Onyx Demon Statuette (Alistair's gift)), a couple of locked Chests, and one of the Gravestones for The Mage's Treasure quest.
Gatekeeper
When the Warden approaches the Mad Hermit's clearing (East Brecilian Forest Map, L3), he will teleport in the middle of the camp, swinging fists to the empty air, dancing and overall being faithful to his name. Engage him in dialogue, and he'll offer to help you reach the center of the Forest if you kill the Grand Oak in the Western Brecilian Forest and provide him with a Werewolf Pelt. The Warden has now various options, as described in the Mad Hermit entry, to receive the help they require to cross the magical barrier in the forest. They all involve a trip back to the Grand Oak so, keep your eyes open for newly spawned patrols in the forest.
If you kill the Mad Hermit, his camp will later be occupied by bandits, and a group of darkspawn will appear by the southern Ancient Tombstone.
There is a Landmark Tent where Dog can activate Mabari Dominance, as well as a nearby locked chest.
The Hermit may become hostile if you stick your hand in the tree stump. It is possible to retrieve a Golden Ring (+1 constitution) from here.
Note: Once you passed through the Magical Barrier (using either the Magical Werewolf Pelt or the Oak Branch) to reach the center of the forest and the ruins, you can no longer trade with the Hermit, nor can you agitate him into attacking you by rummaging through the tree stump.
Witherfang
Past the Southern Ancient Tombstone the Warden will have a brief encounter with another named werewolf, the Gatekeeper, and a couple of his aides.
They will run away before the Warden can do anything, but drop a hint about a "Lady" to be protected. Beyond this point lies the entrance to the Brecilian Ruins (East Brecilian Forest Map, L6).
Note: This may be a good time to clear out your inventory; players have reported requiring over 100 empty inventory slots to pick up every item. If you backtrack to the Dalish Camp, watch out for enemies that may have spawned since you cleared the area.