Introduction
Hello and welcome to this Recollection (extreme) guide !
This is the 4th trial of the Dawntrail expension, and is decently fast-paced fight that requires thinking on your feet. Hopefully, you will find all the tools you need in this guide to help you get through it and eventually down this fight.
Let’s get started right away !
— Vicky.
Prep work
To get through this fight, you will need standard clock positions, and not much more. In this guide, I’ll use the standard clock positions with counter-clockwise markers.
A MT
1 2 R1 R2
D B H1 H2
4 3 M1 M2
C OT
Important mechanics
As you progress through the fight, here are the mechanics you’ll encounter and what they look like when relevant:
You don’t have to read all this right now if you don’t feel like it and immediately skip to the step-by-step guide which will include links back to the list below for each mechanic !
Raid wides
Thorned Catharsis, Perfumed Quietus
Akh Rais
Shock

Donut Akh Rais
also Shock

Towers
Respectively 3-people tower and single person tower.

Tank tethers
Specter of the Lost

Proximity baits
Escelons' Fall | respectively near and far

Akh Morns
Stock Break
Half-arena cleaves
Spearpoint Push, Power Break

The cleave will always happen on the side the sword is pointing when the cast resolves.
Arena change
Her very own special mechanic: Roseblood Bloom. From whereon the arena changes to variations of this:

As you might be able to see, the arena looks like some kind of dartboard with eight slices divided in two discs and a central killzone dot, with some of the tiles being lit up in a brighter red. This difference in brightness can be very hard to see depending on your screen settings and colorblindness. Unfortunately this time around the only difference in shape I could find is possibly even harder to see than the difference in brightness : lit tiles have a triangle shape drawn on them.
Lit | Not lit

The gimmick in this fight is that every time one of those lit tiles is hit by a mechanic, it will extend this mechanic. If a lit tile is hit by — say — one pixel of somebody’s spread AoE, the tile will explode with the same damage and effect as that spread AoE. On top of this, every adjacent lit tile counts as one and the same. So if a mechanic hits the corner of one of them, it will extend that mechanic to all of them !
All in all, avoid standing on those lit tiles while mechanics are going on, unless the mechanics specifically require you to stand on them.
Typhon
Alexandrian Thunder II

Spread
Alexandrian Thunder III

Cones + chariot/dynamo
Thunder Slash

These also come with in → out or out → in AoEs, displayed as follows (in → out in this example).

Rose Markers

Those markers will spawn above your head and, after a short delay, light the tile you are standing on.
Rose Towers

This tower needs one person to soak it, standing anywhere in its lit tile or any connected lit tile.
Chains
Encircling Thorns

These chains always tether DPS to supports if everyone is alive. If not, try to pay attention to whoever you’re chained to and be ready to adjust if needed.