FFXIV AAC Heavyweight M12S Phase 1 Guide – Lindwurm

This guide, shared by Hector Lecture on his YouTube channel, covers the full AAC Heavyweight M12S (Lindwurm) encounter, focusing on clear role responsibilities, Party Finder–friendly positioning, and step-by-step resolutions for each major mechanic. Let's dive in. As always, if you want a quicker way to clear this tier, MmoGah offers FFXIV Boost service for the AAC Heavyweight Savage tier, which is easy and hassle-free. 

General Positioning

This fight primarily uses spread positions. These are role-based, mirrorable, and ordered from north to south. Some mechanics may require minor adjustments to dodge Chrono Cleaves or to preserve melee uptime, but the base spread order remains consistent.

Opening: The Fixer

The fight begins with The Fixer, a very heavy-hitting raidwide AoE.

• Mandatory heavy mitigation
• Under-mitigating will result in deaths

Mortal Slayer

Lindwurm summons eight hands (four per side) and casts Mortal Slayer.

Orb Types

• Green Orbs – Spread AoEs (any role)
• Purple Orbs – Tank busters (tanks only, heavy mitigation required)

Rules:

• Always 2 purple + 6 green
• Orbs spawn two at a time
• Can be both on one side or one per side
• The orb targets the nearest player to the boss hitbox on that side

Tank Assignments

• Main Tank → First purple orb
• Off Tank → Second purple orb

Green Orb Order (Conga Line)

• H1 – First green (left)
• H2 – First green (right)
• M1 – Second green (left)
• M2 – Second green (right)
• R1 / R2 – Third & fourth green on the side with four orbs

Execution Tips

• First players stand against the wall
• Second players stay on deck, inside the hitbox, but not on the wall
• Others wait outside the hitbox
• After exploding, players move outward toward the corners
• Next player slides in like a conveyor belt

Edge Case:

If a purple and green orb spawn simultaneously, the outer orb goes to the innermost player. Tanks must adjust positioning to avoid mis-targeting.

Post–Mortal Slayer

• Group northwest
• Loose spread
• Prepare for Grotesquerie: Act 1

Grotesquerie: Act 1

Debuffs Overview

1. Purple Growth Debuff

• Indicates a directional cleave
• Cleave direction rotates with the player facing

2. Stack Debuff: Always on one role

3. Spread Debuffs: On the opposite role

Puddle Baiting

• Stack tightly
• Bait 4 puddles: First 3 along the north wall, and the 4th swerves inward near the hitbox arrow

During the third puddle, Lindwurm begins Ravenous Reach.

Ravenous Reach Resolution

• Watch the dragon's head direction: Straight down or diagonal
• Dodge to the safe side
• Resolve the stack in the corner
• Turn cleaves outward — mis-aiming will kill teammates

After resolution:

• Tanks move away
• Party stacks on one side
• Blobs drop + tank busters + stack
• Tanks run in opposite directions
• Tankbusters can be stacked with sufficient mitigation

Mitigate another Fixer afterward.

Grotesquerie: Act 2 (Most Complex Mechanic)

Debuffs

• Alpha / Beta pairs
• When the timer expires → tether forms
• Break the tether by running opposite
• Break causes:
  • Spread AoE
  • Magic Vulnerability
  • Tower spawning under Beta

Tower Rules

• Alpha players soak boss-dropped towers
• Beta players soak towers from tether breaks
• Order for both: 3 → 4 → 1 → 2

Simplified Role Logic

Alpha Players

• Alpha 3 & 4: soak blob towers first
• Alpha 1 & 2: break tether first, then soak tower
• After soaking, stand still — you're done

Beta Players

• Run opposite exit to break tether
• Then run opposite exit again to soak a tower
• Final step: sprint out before the final crush

Chronological Flow

• Boss drops 4 blobs
• Cruel Coil pulls everyone to the center
• Alpha 3 & 4 soak blobs
• Alpha 1 breaks → Beta 1 runs opposite → Tower → Beta 3 soaks
• Alpha 2 breaks → Beta 2 opposite → Tower → Beta 4 soaks
• Alpha 3 breaks → Tower → Beta 1 soaks
• Alpha 4 breaks → Tower → Beta 2 soaks
• All Betas escape exit

Splattershed: Moderate raidwide

• Mitigate
• Boss arms explode → dragon arms form

Grotesquerie: Act 3

Growth Mechanics

• Growth direction is fixed
• Start by pointing growth toward the center
• Move opposite growth to the cardinals

Each cardinal has 1 Support and 1 DPS

Floor Break Patterns

• Either cardinals or intercardinals are safe
• Identify by checking AoE at the four-way marker

Cardinal Safe

• Stay cardinals
• Spread adjustments to avoid overlap
• Bind → towers fire between partners

Intercardinal Safe

• Everyone rotates in the same direction (clockwise)
• Supports bottom-left, DPS top-right
• Towers fire in a rotation pattern

Correct positioning ensures towers are caught cleanly.

Dragons & Curtain Call

The platform depends on the previous safe pattern.

Cardinal Platform

Dragons Spawn

• Tanks bait busters diagonally north
• Heavy mitigation recommended

Follow-up

• Dragon's fire spreads to the furthest players
• Tanks move middle, melees near the wall

Curtain Call

• Similar to Act 1
• 5 puddles instead of 4
• Purple spreads must be hit by cleave
• Yellow spreads avoid cleave
• Heavy mitigation required

Afterwards:

• Alpha tethers break
• Supports left / DPS right
• Dodge blobs

Intercardinal Platform

• Tanks bait busters north corners
• Fixer → stack
• Puddles loop counterclockwise NW
• Identify who must be hit by the cleave
• Spread freely inside the cleave if required

After spreads:

• Rush safe zones
• Heal through Splattershed

Mortal Slayer (Repeat): Exactly the same as the first occurrence.

Slaughtershed (Final Mechanics)

Positioning

• Supports slightly north of the hitbox arrow
• DPS on or slightly south

Resolution Rules

• Safe spots: Northern corners
• Stack goes to the corner with blob
• Spreads go to the empty corner

Dragon heads:

• Half-arena cleaves
• Dodge right → then left

Second Slaughtershed

• Roles swap (supports stack, DPS spread)
• Regrown arms cause knockbacks
• Knockbacks alternate sides
• Use knockback immunity if available

Final Slaughtershed

• Same pattern again
• Execute cleanly

Enrage

If the boss is not pushed low enough:

• Becomes untargetable
• Instant party wipe

If the boss reaches 0% before Refreshing Overkill completes:

• Phase transition
• The fight is cleared