This is a guide to the fight Mount Ordeals Extreme (Rubicante) in Final Fantasy XIV. This covers all mechanics found in the extreme trial released in patch 6.3.

I've just released a mini-guide that helps to visualise the easy method of solving Ordeals 3 & 4 shared by Phiefer3. Hope this helps make those parts a bit easier!
   • Easy Ordeals of Purgation 3 & 4 (Mount Ord...  

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Strats are all day 1 strats and improved strats will undoubtedly be found (and probably already exist). Hope you find it useful regardless!

Mechanics order

Phase 1
Inferno - raidwide

Ordeal of purgation - rings (1 line, both red rotate)
Ordeal of purgation - rings (2 lines, outer red rotate)

Shattering Heal - tankbuster

Arch inferno - spinning explosions
-Stack/2-person groups/spread
Conflagration - line cleave
--Stack/2-person groups/spread
Radial flagration - protean


Inferno
Ordeal of purgation - rings (2 lines, purple rotate, two triangle)
Ordeal of purgation - rings (2 lines, purple rotate, two square)

Adds
Big Add - Gnasty torch - DOT
South adds - point tethers out
North adds - tankbuster tethers

Blazing rapture - high raidwide damage

Phase 3
Transforms into wing form

Flamespire brand - flares + stack + spread debuffs
Flamerake - Spinning + or x
1. Dodge telegraph
2. Stack in + flares out
3. Spread

Inferno - spread raidwide + bleed
Scalding signal - Out + baited line aoes
or Scalding ring - In + baited line aoes
Sweeping immolation - get behind + spread/stack + don’t be on the lines
Dualfire - 2x tankbuster cleaves, take NE/NW, group S

Untransforms

Ordeal of purgation - rings (1 line, purple and red rotate)
Ordeal of purgation - rings (2 lines, purple rotate) (square+triangle)
Inferno

Transforms

Flamespire Claw (Limit cut)
Have 7 and 8 grab tether
Odds take cleave at 1
Evens take cleave at 2
After cleave, grab tether on your side

Inferno (Spread version)
Scalding ring/signal
Sweeping Immolation
Dualfire

Untransforms

Ordeal of purgation - rings (1 line, purple+red )
Ordeal of purgation - rings (2 lines, purple rotate?)

Inferno (enrage)

0:00 Introduction
0:39 Ordeals of Purgation 1&2
3:00 Arch Inferno
5:15 Ordeals of Purgation 3&4
6:59 Adds Phase
9:13 Flamespire Brand
13:06 Scalding Signal/Ring
13:39 Sweeping Immolation
16:05 Ordeals of Purgation 5&6
17:35 Flamespire Claw
20:50 Special Thanks!