A descent strike from the bottom of Nessus, re-taught in modern Grandmaster Vanguard Alert language. Punch through a Cabal Red Legion landing into the Vex conflux, ride the Cabal drill across the dig site, manage champion frame coverage instead of old Artifact mods, and finish Protheon, Modular Mind as the arena floor falls away beneath it through three elemental phases.
Faction
VexCabal Red Legion in early sections
Combat range
OpenDig-site lanes, then the falling Spire arena
Champions
Weekly setTypes follow the weekly modifier set
Boss
ProtheonModular Mind · descending phases
Wipe risk
Drill + fallsTraversal & lost cover, not the health bar
00 · Read This First
What this run really is
The Inverted Spire is a downward strike — you start on the Nessus surface and chase a Cabal dig crew through the planet's torn-open shell into a Vex excavation. In a Grandmaster Alert its danger isn't the boss's health bar; it's the dig-site traversal (a moving drill and platforming over a chasm) and the loss of cover in the boss room as the floor falls out from under you. Treat the descent as a hazard course and the boss as a positioning fight, not a DPS race.
The one-sentence identity
Break through a Cabal Red Legion landing into a Vex conflux, ride the Cabal drill across the dig site without getting crushed or falling, then burn Protheon, Modular Mind as it cycles elemental phases and the arena floor drops a tier each time.
Everything you bring serves three jobs: survive the traversal, cover the champion types present, and deal burst on Protheon between immune phases while clearing its summoned Vex. Build for those, not for the trash.
What old guides get wrong
They tell you to slot a seasonal anti-Champion Artifact mod. Stun is frame-intrinsic now — bring the right archetypes (weapon guide).
They quote a fixed champion list. GM champion types and counts follow the weekly modifier set.
They mash the hazards together — "dodge crushing gears and rotating shields in the boss room." In truth the crushing drill is the dig-site traversal, and the boss room is the elemental-phase fight on falling floors. Two different places.
They name a specific Adept reward. The chase is the weekly Tier 5 weapon, and it changes every reset.
01 · Champion Coverage
Cover the frames, not the mods
Anti-Champion is built into weapon frames now — there's no Artifact mod to forget. Bring archetypes that cover the types the week assigns. Champion types follow the weekly modifier set.
Per weekly modifier set
Barrier
› Pierce / break the shield
Vex Hobgoblins (and Cabal Centurions/Phalanxes in the early sections) carry the Barrier tag when the weekly set lists Barrier. Bring a Barrier-intrinsic frame to strip the shield, then finish. Don't waste a Super into an unbroken shield.
Some weeks
Overload
› Disrupt to stop the heal
Overload Minotaurs are the type most often cited here. They regenerate and teleport; an Overload frame interrupts them so they stop healing — focus them first or they reset the room.
Some seasons
Unstoppable
› Stagger before it charges
When the weekly set lists Unstoppable, expect Unstoppable Minotaurs/Hobgoblins or Cabal heavies. An Unstoppable frame staggers them at range — stun, then delete before they close.
The modifier readout, every time: (1) enemy pressure — which champions, shields, and faction units; (2) weekly modifiers — surge, threat, banes, player stakes; (3) the single modifier most likely to wipe a casual team; (4) one build swap that answers it. Run that readout on the launch screen before every GM Alert. Champion types follow the weekly modifier set. The hub's modifier glossary explains Medusa, Focused Fire, and the rest.
02 · The Route
Down the Spire, top to bottom
Four beats: the Cabal landing, the Vex conflux descent, the drill / dig-site traversal, and Protheon's arena at the base. The whole strike funnels downward — the skill is when to push, when to hold, and when to stop shooting and watch the drill. Here's the route at a glance; each beat below carries its own notes.
Full routeNessus surface → the dig site at the base
"Find the breach without spending your tokens on the easy part."
The loop
Drop into Arcadian Valley on Nessus and push through the initial Cabal Red Legion encampment guarding the dig.
Hold the first piece of hard cover and let the team stack before crossing open ground toward the torn-open structure.
Thin Psions and Legionaries early, then push into the breach toward the Vex conflux — the cheap kills snowball into chip damage if ignored.
PaceThis beat is forgiving on Normal and lethal on GM only if you sprint blind. Move as a group, cover-to-cover; a hero rush here burns a revive token you'll want at the boss.
ThreatMatch the weekly threat element with a resist mod before the first real fight — GM chip damage from massed Cabal adds up fastest in the open.
2
Beat · Vex Conflux Descent
The Conflux Descent
"The faction flips to Vex — and the strike starts pulling you down."
The loop
Access the Vex conflux and traverse deeper. The enemy mix shifts to Goblins, Minotaurs, and a Hydra as the path funnels into the excavation.
Expect the first champions here — clear them with the matching frame coverage before pushing. Don't leave a teleporting Minotaur alive behind you.
Use the broken terrain as cover and peek one angle at a time; the descent has long Vex sightlines and the Hydra punishes a static team.
ChampionThis is a likely Overload Minotaur / Barrier Hobgoblin zone in seasons that run it — but the live set rotates. Call the type out, strip or disrupt with the right frame, then collapse together.
SightlinesIf Medusa or No Radar is active, the open conflux gets dangerous. Shorten sightlines, hold corners, and don't hard-scope a Hydra eye you can't disengage from.
ScoreIf a scoring modifier is up, the descent banks easy points — but a wipe costs more than a fast lane. Clean beats quick.
3
Beat · Drill Site / Dig-Site Traversal
The Drill Site
"This is the part that actually kills you — and the boss isn't even here yet."
The loop
Clear the drilling-site security at the edge of the chasm, then prepare to cross. This is where the strike's real traversal hazard lives.
Board / ride the Cabal drill and cross the dig site (the drill is a moving platform and a crushing hazard at once) — time your moves so you're never between the drill and a wall.
Make the platforming jumps across the chasm cleanly. A missed jump or a hit from the drill is an instant death and a burned token, not a chip.
DrillThe moving Cabal drill is the #1 cause of death in the descent. Treat it like a hard environmental hazard — stop shooting, watch its travel, and only move when your path is clear. No "I'll make it."
FallsThe chasm jumps are lethal in GM where you can't tank a stray hit mid-air. Cross one at a time, don't bunch on a moving surface, and keep a movement ability in reserve.
AmmoThis is the last calm stretch before the boss. Top up Special and Heavy before you commit to the crossing, and agree who grabs bricks on the far side.
"Its health bar isn't the threat — your cover is, and it keeps disappearing."
The loop
Protheon, Modular Mind — an Ultra Vex Minotaur / Vex Mind — drops into the dig site at the base of the Spire. Find cover before you start shooting.
Damage the head crit until it is knocked off, then shift to the center of the body. The boss's appearance progressively breaks down as it takes damage — that's your visible health read.
Protheon cycles three elemental phases— Void, then Solar, then Arc. Between phases it goes immune and summons Vex reinforcements (Goblins / Minotaurs).
On each phase transition it dissipates the floor, dropping the fight to a lower arena tier. Be ready to fall, re-find cover, and re-establish position on the new floor.
Clear the summoned adds during every immune window before re-engaging. Pushing the boss into a summon phase with adds still up is how teams get swarmed.
Repeat — burst the crit, clear the adds, ride the floor down — until Protheon is destroyed. Bank a revive token in reserve for the last tier.
CoverEach floor drop resets your cover. Loss of cover plus Arc pools and fire spreading across the floor is the #1 cause of death here — relocate to hard cover the instant the floor changes, before you resume DPS.
AddsDon't push the boss into its add-summon phases with reinforcements still alive. Clear the summoned Minotaurs / Goblins (plus any champions) first, then commit to the crit.
BurstDamage windows are short because you keep repositioning around the falling floor. Burst the head crit when it's exposed, then the body center — a heavy you can fire-and-reposition beats slow sustained DPS.
PhasesProtheon runs its elemental shields in order: Void → Solar → Arc. Match your DPS element to the surge regardless.
Map · Protheon's ArenaBoss · Descending Floors
Protheon (crit → body)Floor drop / phaseCoverSummoned Vex
03 · Loadout by Role
Bring four jobs, not four guns
A GM team is happiest when each player owns a job. Full build cards live in the classguides and the Prismatic deep dive — these are the jobs to fill and the archetypes that fill them. Names rotate with the meta; the jobs don't.
Anchor / Control
Room control + self-sustain
Hold space and keep the team topped through Vex add waves.
Warlock — Void Devour or the Prismatic Getaway loop.
Titan — Strand Banner of War for team woven mail.
A reliable add-clear Primary that respects the surge.
Champion Lock
Frame coverage
Carry the intrinsic stuns the week assigns.
Barrier + an Overload frame as the common baseline here.
Swap in an Unstoppable frame on seasons that run it.
See the weapon guide for which archetypes carry each stun.
Boss Burst
Damage between floor drops
Burst windows beat sustained DPS — the floor keeps moving you.
Hunter — Nighthawk Golden Gun for a clean single-shot nuke on the crit.
Titan — Thundercrash as a burst swap.
A heavy you can fire-and-reposition (rocket / LFR).
Emergency Support
Safe revive / reset
The insurance that saves a token on the traversal and the boss.
Hunter — Void invis (Gyrfalcon / Omnioculus) for safe rezzes.
A healing or overshield tool for the lost-cover boss room.
A debuff (Tractor / Div) to speed the Protheon phases.
Loadout note: these are the mid-2026 (Monument-era) jobs and archetypes — match the weekly surge when you pick your elements. For full, current builds, the class pages go deeper than any single route guide.
04 · Modifier Adjustment
What changes when the modifiers do
The route is evergreen, but the week's modifiers decide how you play it. The most common GM swings and the one adjustment each one asks for:
Medusa
Looking at affected enemies stacks Stasis slow toward a freeze. Lethal on the drill crossing and the boss floor — shorten sightlines, peek-and-cover, and never hard-scope a Vex eye you can't disengage from while you're mid-traversal.
No Radar / Blackout
You lose your spawn warnings and melees hit harder. Clear corners in the conflux before committing, hold cover, and call summoned Vex positions by voice in the boss room.
Focused Fire
Heightened incoming damage. Tighten cover discipline everywhere and shorten your exposure windows — peek, fire, drop back. The lost-cover boss room and the open drill crossing are twice as punishing under it.
Harsh threat / surge
Slot the matching resist mod for the threat element and match your DPS element to the surge on Protheon. A mismatched surge can double your phase count against an elemental boss.
Champion types follow the weekly modifier set: the exact champions, banes, surge, threat, and player stakes come from the week's GM Alert modifier list, shown on the launch screen.
05 · Common Wipes
Why teams actually lose this
Almost none of it is the boss's health bar. The Inverted Spire wipes groups in four predictable ways — kill these habits and the run is yours.
1
The drill and the chasm
Being crushed by the moving Cabal drill or falling during the dig-site jumping sections ends runs before the boss even loads. Stop shooting, watch the drill, cross one at a time, and never gamble a jump in GM.
2
Champion concentrations, wrong counters
The chasm and multi-level gauntlet stack champions. Getting overwhelmed without matching champion frames staged for the active types is a fast wipe — bring the matching frames.
3
Losing cover in the boss room
As Protheon summons Vex adds and Arc pools / fire spread across the floor, lost cover turns into chip damage and burst deaths. Re-find hard cover the instant the floor drops — don't DPS from open ground.
4
Over-pushing into summon phases
Pushing the boss too aggressively into its add-summon phases instead of clearing reinforcements gets you swarmed by Vex (Minotaurs / Goblins) plus champions. Clear the room, then commit to the crit.
Weekly reward: when the Inverted Spire is the active Grandmaster Alert, a Grade B or better clear awards the week's featured weapon at Tier 5 (first clear pre-masterworked with its origin trait). The weapon changes weekly — this route is evergreen, the reward is not. See the hub reward ladder.
Free guides · made by ThePsychDr
These guides stay free.
No paywall, no login. If a guide saved you a wipe, the videos and the people who watch them are what keep this site going.