Telesto doesn't fire a bolt, it plants one. Every shot sticks projectiles that hang for a beat and then go off as a delayed Void blast — a wall of floating mines you walk the room into. On Void Hunter you load those mines with Volatile Rounds off Gyrfalcon's, so every delayed detonation also detonates the volatile — two explosions per bolt, chaining through the pack. The whole trick: emerge invisible, paint the room with sticky Void mines, watch it cascade.
The weapon
Unplanned Reprieve (exotic perk):"Fusion projectiles attach and detonate with a delayed Void blast."
Telesto Catalyst — Deeper Pockets / Harbinger Seethe:"Deeper Pockets: Increased ammo reserves. / Harbinger Seethe: After activating Harbinger's Pulse multiple times, [Alternate Weapon Action] to cause a rain of projectiles on your next direct hit with this weapon." The catalyst's underlying perk is Harbinger's Pulse — "Multikills with Void damage immediately reload this weapon from reserves."
What it does: a single trigger-pull throws a burst of bolts that stick to whatever they hit (surface or body), pause, then erupt in staggered Void detonations. Against a clustered pack one shot is several overlapping blasts. Because the kills are Void multikills, Harbinger's Pulse reloads the gun from reserves for free — so Telesto self-sustains its own add-clear loop, and Deeper Pockets keeps the reserve pool deep enough to do it all encounter. Harbinger Seethe is the spike: stack Harbinger's Pulse reloads, then [Alternate Weapon Action] to make your next direct hit rain extra projectiles — a free burst-mine overload on a priority target.
Loadout
Slot
Pick
Why
Subclass
Nightstalker (Void)
The element matches the gun — Volatile and Devour both feed off Telesto's Void kills.
Super
Shadowshot: Deadfall
35% weaken + suppress + groups the pack into one spot — exactly where Telesto's mines want them, and weaken multiplies the blasts.
Class ability
Marksman's Dodge
Reloads on dodge (redundant with Harbinger's Pulse) and resets the Vanishing Step invis cycle on demand.
Melee
Snare Bomb
Cheap, throwable invis-on-detonation + weaken delivery; re-arms Gyrfalcon's Volatile without a kill.
Grenade
Vortex Grenade
Lingering Void zone; with Echo of Undermining it weakens, with Echo of Instability it re-grants Volatile.
Aspect 1
Vanishing Step
Dodge → invisible. The invis half of the Gyrfalcon's engine; `+2 Aspect Energy Capacity`.
Aspect 2
Stylish Executioner
Any elemental-debuffed kill → invisible + Truesight. Volatile/weaken kills (which Telesto makes nonstop) loop you back into invis hands-free.
Fragments
Echo of Instabilitygrenade kills → Volatile Rounds — a second Volatile source so the gun stays loaded between invis cycles
Echo of Harvestweakened kills → Orb + Void Breach
Echo of Starvationpick up Breach/Orb → Devour
Echo of UnderminingVoid grenades weaken — feeds Harvest and the blasts
Echo of Reprisalkills while surrounded → Super energy — Telesto is always surrounded
Exotic — Gyrfalcon's Hauberk (Chest)
See Me, Feel Me:"Your Void weapons gain Volatile Rounds after you emerge from being invisible. When you are invisible and defeat a combatant while using a finisher, all of your weapons gain bonus damage; you and your nearby allies gain a reserve overshield and improved class ability regeneration. These reserve overshields can be deployed by using a class ability."
This is the build. Emerge from invis → Telesto's sticky bolts are now Volatile → every delayed Unplanned Reprieve detonation also pops a volatile burst, and volatile spreads on kill. One Telesto shot into a pack becomes a chain of doubled Void explosions. The finisher line bolts a fireteam overshield + damage buff on top for the hard rooms.
Why this works (the mechanics)
Telesto is a Volatile delivery system, not a single gun. Unplanned Reprieve plants multiple delayed detonations per shot; Gyrfalcon's makes each of those a volatile detonation too. The bolts already explode — Volatile just doubles every explosion and lets it chain. No other Void weapon multiplies off Gyrfalcon's as hard, because no other Void weapon fires this many separate detonations per trigger-pull.
The invis ↔ Volatile loop is self-closing. Vanishing Step gives invis on dodge → emerge → Volatile Rounds → Telesto's volatile blasts kill a debuffed pack → Stylish Executioner grants invis again (any elemental-debuffed kill) → emerge → Volatile refreshed. You re-arm Volatile by using it. Snare Bomb and Echo of Instability are backup arms for when you can't be bothered dodging.
The gun reloads itself. Harbinger's Pulse: Void multikills → instant reload from reserves. Telesto's whole job is Void multikills, so it never stops to reload mid-clear, and Deeper Pockets keeps the reserves deep enough to never run dry. Marksman's Dodge is a redundant backup reload.
Weaken is the force-multiplier and the Devour fuel. Deadfall (35%), Snare Bomb, and Undermining'd grenades all weaken — weaken is a debuff-bucket multiplier that boosts every detonation for the whole fireteam, and every weakened kill (Echo of Harvest) spawns an Orb + Void Breach → Echo of Starvation turns that into Devour (full heal + grenade refund on kill). The add-clear pays for its own survivability.
Special ammo, infinite uptime. Telesto is a Special fusion — but between Harbinger's Pulse reloads, Deeper Pockets reserves, and Special-ammo economy mods, you're never starved. It plays like a primary add-clear tool that happens to hit like a heavy.
Stats & mods
Weapons 200 → Class 100+ → Super. Weapons stat scales Telesto's PvE damage vs minors/majors directly (9.7.0). Class high to keep Marksman's/Vanishing Step dodge — the invis cycle — on a short cooldown. Super third to feed Deadfall.
Archetypes: a Weapons/Class-favoured set (e.g. Gunner/Specialist pieces); set bonus is garnish only — pick rolls first.
Mods:
Helmet: Harmonic Siphon (Void kills → Orbs — Telesto floods these) · Heavy Handed / Ashes to Assets for ability return.
Class item: Powerful Attraction (dodge vacuums orbs into Devour/Starvation) · Reaper (dodge → next kill spawns an extra Orb).
Special-ammo: Special Finisher / Special ammo finder to keep reserves topped beyond Deeper Pockets in long encounters.
Where it shines
Add-dense PvE: strikes, GMs, dungeons, Onslaught — anywhere enemies cluster. One stuck-mine shot wipes a pack; volatile chains finish the stragglers. This is a premier add-clear loadout, not a boss-DPS one.
Champion coverage — flag. The manifest does not state Telesto's fusion frame (Precision/Rapid-Fire/etc.) or RPM, so its Anti-Champion 2.0 intrinsic stun is unconfirmed (see Verify). Telesto carries no bespoke champion stun in its perk text. Cover champions through the kit instead: Deadfall suppresses + Snare Bomb suppresses (Overload-style interrupt + weaken), weaken thins champion health for the team, and you should slot a secondary/heavy whose archetype carries the Barrier/Unstoppable stun you need for the activity.
Survivability: Devour (Starvation) + Gyrfalcon's reserve overshield + invis (Vanishing Step / Stylish) — three layers, all fed by the same Void kills.
Artifact - NPA Repulsion Regulator
The dedicated Void artifact, tuned exactly to this loop: a second Volatile source for Gyrfalcon's, Void Breaches that feed Devour and overshields, and Overload on the Vortex grenade the build already throws.
Tier 1:Volatile Flow (Orb pickup re-arms Volatile on Telesto — a backup to the invis emerge, so the gun stays loaded between dodges) - Unto The Breach (Void-debuffed kills make Void Breaches — Telesto's weakened/volatile kills now print Breaches for Echo of Starvation's Devour)
Tier 2:Protective Breach (Void Breach → overshield, stacking a fourth survival layer onto Devour + invis + Gyrfalcon's reserve overshield) - Overload Grenades (Vortex grenade now stuns Overloads — the build's Void grenade carries a champion breaker) - Bricks From Beyond (Void weapon kills drop Heavy progress, keeping a stun-carrying heavy fed)
Tier 3:Supernova (picking up a Void Breach makes your next Void hit a weakening pulse — free fireteam weaken that multiplies every detonation) - Void Weapon Channeling (temporary Void weapon damage bonus after a Void kill — straight onto Telesto's blasts)
Mod selection (masterworked — full allocation)
Piece
Mod · cost
What it does
Helmet (7/10)
Special Ammo Finder3e
Increases the effect of all contributions towards the Special ammo meter.
Harmonic Siphon1e
Rapid Arc weapon final blows create an Orb of Power. Rapid Solar weapon final blows create an Orb of Power. Rapid Stasis weapon final blows create an Orb of Power. Rapid Void weapon final blows create an Orb of Power. Rapid Strand weapon final blows create Orbs of Power.
Ashes to Assets3e
Gain bonus Super energy on grenade kills.
Arms (7/10)
Heavy Handed3e
Your powered melee final blows create Orbs of Power.
Fastball1e
Increases grenade throw distance.
Utility Kickstart3efill
When your class ability energy is fully expended, your Armor Charge is consumed and you gain class ability energy for each Armor Charge used.
Chest (5/10)
Void Resistance1e
Reduces incoming Void damage from combatants.
Concussive Dampener3efill
Reduces incoming area-of-effect damage from combatants.
Sniper Damage Resistance1efill
Reduces incoming damage from combatants that are at long range.
Legs (7/10)
Void Weapon Surge3e
Your Void weapons gain a small bonus to damage while you have any Armor Charge. Your Armor Charge now decays over time.
Orbs of Restoration1e
Picking up an Orb of Power grants a small amount of energy to your ability with the least energy.
Void Weapon Surge3efill
Your Void weapons gain a small bonus to damage while you have any Armor Charge. Your Armor Charge now decays over time.
Class Item (4/10)
Special Finisher1e
Finishers generate Special ammo for the whole fireteam.
Reaper1e
Shortly after using your class ability, your next weapon final blow spawns an Orb of Power.
Powerful Attraction2e
Automatically collects nearby Orbs of Power when you activate your class ability.
All 15 sockets used, 10 energy per masterworked piece; costs from the manifest. Core mods are the build's engine; fill mods are strong defaults — swap freely (chest resists should match the activity's damage types).