Dragon Age: Inquisition

While the other guides do an acceptable job, neither of them really goes in-depth with their instructions, so I figured I'd write a solution for people - like me - who struggled to complete this achievement. Basically, this achievement is for looting all four of the Fen'Harel statues found throughout the DLC. You're looking for giant wolf statues like the ones found in the Exalted Plains in the base game. Each of them has a sort of puzzle attached to it that unlocks its cache.

I don't think the first statue is missable. It's found naturally as you progress through the story. When you're following the blood trail through the eluvians, you'll come to an area where elven spirits and qunari block your path. At the end of a long hallway, you'll see the statue. Illuminate the veilfire brazier that the statue is looking at and it will move out of the way to reveal a set of stairs and its loot cache will appear at its paws. You must loot the cache for achievement credit.

The second statue is found in the Deep Roads, but as far as I can tell, it is not accessible until after you find the third statue. After you enter the eluvian leading into the Deep Roads and fight the qunari waiting for you, you'll travel along the path until you come to a chasm with a large amount of qunari on the other side. There is a hallway directly after this chasm that is dark. If it's your first time here, you'll be prompted to use your anchor to illuminate the area. Remember this spot so you can return to it later.

The third statue is found in the Sundered Library. In this area, there are several floating islands that you'll have to travel to in order to find the Viddasala. When you step out of the eluvian leading to one of these islands, you'll see a circle of statues holding veilfire braziers. This is the island you need. Go upstairs, above the circle of statues, and travel through the eluvian there to reach an area called "Scholar's Retreat." In this area, there is a ledge blocked by purple flame. You need to make your way around these flames to a hidden flight of stairs. Ascend the stairs and walk around the path to find the statue. When you activate the button there, a green orb will fly out of it and back downstairs through the eluvian and ignite the veilfire braziers in the circle. The veilfire only stays lit for a short amount of time, so you'll need to jump from the statue's ledge onto the lower ledge, go through the eluvian, jump from that ledge down to the circle of statues, and light a veilfire torch of your own. Bring this torch back to the wolf statue and use it to light the brazier on the wall next to it. Doing this will reveal the statue's cache.

Tip: If you're a necromancer mage, you can use Simulacrum to move through the purple fire with ease. You'll die, but your spirit can walk through the rest of the flames and ascend the stairs. Be sure to cast a spell to force your spirit to drop the torch before it expires or you'll have to get another one. Then, just go back to the area where you dropped the torch with your real body and continue.

After you return to the Winter Palace, you'll be tasked with finding the Viddasala. Don't do this. Instead, return to the Deep Roads and go back to the dark hallway from earlier. Now that you have the damaging anchor ability, you can set off the gaatlok barrels here. Doing so will expose a room hiding an eluvian. Travel through the eluvian and you'll see a veilfire brazier. Take a torch, go into the next room, and walk to the mural on the wall, exposing a rune there. The statue will turn around to look at the rune. Press the button on the statue's back to raise the stairs up to the other brazier and ignite it to unlock the cache.

The final statue is beyond the keystone eluvian. Be sure to bring a mage with you before you go! After you come through the eluvian, you'll fight through some qunari and quickly reach a locked door in the area marked "Courtyard." On the opposite side of the area from the bridge, you'll see a large tower. Climb the stairs to reach the second floor of the tower, kill the qunari there, and go down to the basement where you'll find the statue. Have a mage ignite the veilfire brazier in front of the statue, take a torch, and then climb to the top floor. Ignite the brazier near the halla statue first, then the brazier on the floor. Go back to the bottom floor and the statue will now reveal the final cache.

Tip: If you've missed any of these, you can backtrack until you go through the keystone eluvian. When you're told to pursue Viddasala, you can ignore that and travel through any of the other eluvians to get collectibles you've missed. Good luck!

I used this video...just do them in the order the video show

For anyone searching around; beware minor spoilers here. I'll be vague to avoid ruining it if possible.
NOTE: Make sure once you finish the puzzles to LOOT the boxes on the staute for it to count. It's not enough to just complete the room puzzles.

1st as part of the story, light the torch the statue is looking at among the many in the room.
2nd when you get to there will be explosive barrels hiding a mirror just after you enter, blow them up and go through. If you struggle with this, try the anchor discharge next to them and they should explode. NOTE:
3rd is in the library, press the wolf button and go back to the previous area to find the ring of sconces now lit
4th is in the supply tower, just before going into the big door locked with a wheel turning puzzle. Light the bottom floor, then the top floor hallah, then the bird of prey, then return to the basement for the reward

Hope that helps!