Your first objective is to reach the Primal Fragment before the boss' initial "Light Explosion" attack. This is the her primary attack the boss and will deal damage if you are exposed even a little.

NOTE: hover over images to see a description of what's going on.



As soon as the cutscene ends and you see the boss hovering in the air ahead of you, IMMEDIATELY SPRINT left to jump onto the platform and take a hard right around the pillar to get safely behind the large crates.





Note: The trick in this fight is to try to keep your light meter showing maximum darkness. Unless you are particularly close to the boss, doing so should ensure you take no damage from her primary attack.

As soon as the attack ends, dart for the Fragment. Don't wait for her response; grab the Fragment and do a 180 to the exact same spot you were just waiting (behind the large crates). Stay crouched and approximately in the center behind the crates and you should be safe during her other attack, which is a channeled Damage Over Time attack.

The next Fragment is the hardest to get to because you will be exposed for *almost* too much time to get out of the light.

Once all goes dark from her first channeled attack, drop down to the room below, through the opening between the landing you started on at the beginning and the floor you are on now (i.e., the space you jumped over when getting to the crates originally).

There is a "clone" patroller so wait for her to come into the room then exit. You'll take damage and be discovered if you bump into her. As soon as she is back outside, go through the same door, but veer left to get behind the first colum/stack of crates.





Using the shadow cast on the ground as a guide, keep yourself in the dark while the boss "lights up" for her primary attack. You are only truly safe as long as she isn't right next to you and you are completely in shadow. One the attack finishes, immediately sprint for the next pillar, once again, staying in the shadow cast by the pillar and waiting for the attack to finish.



Your initial goal is to get up on top the upper deck using the grapple point. This part is tricky as you will be exposed for a long time. You need to sprint the INSTANT the attack is over, climb up and WAIT in the shadow of the wall post/pillar.



The second Fragment is dead ahead on the bridge of planks that connect the two upper decks. Once again, wait for the attack to end, and bolt for the Fragment.



The INSTANT you have the Fragment, move a little further across the planks (such that you are past the pit below) and the turn to drop into the area AWAY from the boss and her clones. Get behind the wall and wait there.



This is a safe area and no clones come in here. You should see the corpse of Orion diagonally across from you.



You can take a breather in this area, and are now staged for the final Fragment.

The light attacks don't seem to start until you completely exit this area, so take your time. You can peer out around the corner to see the clone patrol. You need to wait until she is well away from the far pillar as this is where you need to go.



Bolt out around to the left and hug the wall. Head for the pillar ahead, and DO NOT attempt to jump to the right across the open area to the Fragment. I tried several times and the slight pauses with each jump add up to too much time and she'll get an attack off before you get there.

Wait in the shadow on last time, and then round the pillar grab the final Fragment.





When prompted, approach the "boss" back in the room you just left and a cutscene will ensue and the game/chapter ends.

One last tip: do yourself a favor and check the mission objectives often. At least once I made it to the pillar just before the last Fragment and found I had inexplicably taken damage somewhere.

That's it! I will add screenshots with markups as soon as I get them. Good Luck!