Ergo Sum — Gathering Light (Hunter)
The only sword built to be put away. Final blows stack Gathering Light; stowing dumps the whole stack into melee, grenade, and class energy at once — a manual Transcendence pump. The catalyst closes the loop the other way: Transcendent-grenade damage refunds Ergo Sum ammo. So you swing to charge, stow to ability-spam, go Transcendent, throw the grenade that makes more sword, and swing again. It's a Prismatic Hunter that fights with its abilities and reloads them with its sword.
The weapon
Intrinsic — Final blows with this weapon grant stacks of Gathering Light, improving guard stats and lunge range.
Catalyst — Transcendent Steel: Dealing damage with a Transcendent grenade grants Ergo Sum ammo.
The other half of the intrinsic — stowing the weapon consumes all stacks, granting melee, grenade, and class ability energy — is the documented in-game behaviour the whole build turns on (see Verify: the encyclopedia dump captured only the first clause). Read the two together and the playstyle writes itself. Held, Ergo Sum is a swinging melee weapon whose guard and lunge grow as you kill (Gathering Light is the same buff Traveler's Chosen uses); stowed, the accumulated stacks become a burst of melee + grenade + class energy. The more you kill before you holster, the bigger the ability dump. The catalyst then hands you Special ammo back specifically for spending Transcendence — which on Prismatic you build by alternating Light and Dark abilities, the exact abilities Ergo Sum just paid for. Nothing else ties a weapon this tightly to the Prismatic Transcendence economy.
Loadout
| Slot | Pick | Why |
|---|---|---|
| Subclass |  Prismatic Hunter | The only kit with Transcendent grenades — the catalyst is dead on any other subclass. |
| Super |  Silence and Squall (Stasis) | Storm + freeze that feeds the Dark side of the Transcendence bar; Star-Eater turns the orb flood into an overcharged cast. |
| Class ability |  Gambler's Dodge | Melee energy on dodge (scaled by the Melee stat) — a second melee charge on top of the stow-dump. |
| Movement |  Triple Jump | Extra mid-air control to reposition between a stow-dump and the next pack you swing into. |
| Melee |  Combination Blow (Arc) | Kill → heal + escalating melee damage + full melee refund; the on-foot kill engine that isn't the sword, so Gathering Light stacks survive the holster. |
| Grenade | Grapple / Threadling | Grapple closes on packs and makes Tangles; the Transcendent throw is what the catalyst rewards — pitch it into a pack for the ammo refund. |
| Aspect 1 |  Stylish Executioner | Any elemental-debuffed kill → invisibility + Truesight; free safety between stow-dumps. |
| Aspect 2 |  Winter's Shroud | Dodging slows nearby targets — slow is a Darkness debuff that lights Stylish and feeds Transcendence, and pairs with Gambler's melee refund. |
| Fragments | Balance · Honor · Blessing · Bravery · Generosity | Top both ability halves of the dump, convert Tangles/pickups to Transcendence, heal off melee, weaponise the sword, and flood orbs (see below). |
| Exotic armour |  Star-Eater Scales (Leg Armor) | This build is an orb fountain, so Feast of Light keeps Silence and Squall overcharged for a 70% damage cast plus heal and overshield. |
| Weapons | Strand/Stasis Kinetic Primary + Solar/Void Special | The Darkness Primary feeds Stylish and Facet of Bravery; the Special holds champions and bosses while Gathering Light recharges. |
Facet of Balance Light kills → melee, Dark kills → grenade — both halves of the stow-dump get topped further
Facet of Honor Elemental pickups / Tangle destruction → Transcendence — Grapple Tangles feed this
Facet of Blessing melee final blows start health regen — Combination Blow is constant healing
Facet of Bravery powered-melee kills → Unraveling Rounds on Strand weapons — a Strand Ergo Sum eats that
Facet of Generosity Transcendent kills → ally orbs
Why it works (the mechanics)
- Stowing is the build, not a footnote. Gathering Light pays you for killing then holstering. Stack 5–10 kills, swap to the Primary, and the dump refills melee + grenade + class in one swap. The optimal habit is to swing the sword into a pack, holster mid-fight, and spend the abilities it just bought.
- The catalyst makes the sword self-feeding. Transcendent-grenade damage grants Ergo Sum ammo. On Prismatic you reach Transcendence by alternating Light and Dark abilities — which the stow-dump just refunded — so the grenade that crests the bar also restocks the weapon that built it. The loop never asks for a Special brick.
- Combination Blow keeps the sword's stacks alive. Killing on foot with the Arc melee (and healing off it via Facet of Blessing) means you don't have to spend Ergo Sum to keep fighting — so its Gathering Light stacks ride until you choose to cash them, maximising the dump size.
- Two debuff sources light Stylish for free. Winter's Shroud slow (on dodge) and Facet of Bravery / a Stasis-or-Strand Primary mean almost every kill lands on a debuffed target → invisibility + Truesight between dumps. Safety is automatic, not a cooldown you babysit.
- Everything converges on Transcendence and orbs. Facet of Balance tops both ability halves, Facet of Honor turns Grapple Tangles and Stasis/Strand pickups into Transcendence, Facet of Generosity floods orbs while Transcendent — and Star-Eater turns that orb flood into an overcharged Super on demand. One kill loop powers melee, grenade, Super, and the sword's ammo at once.
Stats & mods
Melee 200 → Super → Class. Melee 200 maxes Combination Blow / Gambler's refund and the melee half of every stow-dump; Super feeds Star-Eater's overcharge cadence; Class buys dodge uptime (Winter's Shroud slow + Stylish both key off the dodge). Grenade rides as the secondary dump target; Health is the dump stat — Combination Blow heals, Facet of Blessing heals, Star-Eater overshields, Stylish goes invisible. Lean Brawler / Specialist armour (Melee–Super–Class favoured), then stat-tune +Melee / −Health.
Mods:
- Boots: a Scavenger matching your Ergo Sum element (bonus sword reserves on Special-ammo pickup) +
Recuperation (orb pickup → health) for the orb-heavy loop. - Arms:
Heavy Handed (powered-melee final blows create Orbs of Power — Star-Eater fuel) + Momentum Transfer (grenade damage → melee cooldown, topping the dump's melee half). - Chest:
Concussive Dampener or an elemental Resistance matching the room — survivability while you swing into packs. - Class item: Bomber (class ability → grenade cooldown) +
Powerful Attraction (dodge vacuums nearby orbs into Star-Eater). - Surge: a Weapon Surge matching your Ergo Sum element (and ideally your Primary), live while you hold Armor Charge.
- Anti-Champion: none intrinsic — Ergo Sum carries no champion stun and these artifact picks add none, so bring Barrier/Overload/Unstoppable on your Primary/Special frames.
Artifact — Tablet of Ruin
A Strand-rolled Ergo Sum, a Grapple-Tangle/Threadling loop, and a Star-Eater orb fountain all point at the Strand artifact: it turns this build's orbs, Tangles, and severs into a self-sustaining Unravel engine, while its Kinetic/Super mods feed Transcendence and the Super cadence. Champion stun still comes from your guns — this pool amplifies the loop, not the breakers.
Picks (2/3/2): Unraveling Orbs · Elemental Siphon — Vile Weave · Horde Shuttle · Maligned Harvest — To Shreds · Elemental Supercharger
Unraveling Orbs — picking up an Orb of Power or a Tangle grants Strand weapons Unraveling Rounds, so the orb fountain weaponises a Strand Ergo Sum directly.
Elemental Siphon — Kinetic / Super-matching rapid kills spawn an Elemental pickup of your Super element, feeding Facet of Honor's Transcendence and adding orbs.
Vile Weave — Grapple Tangles sever on hit and refund Tangle cooldown when picked up, the core Strand application this build leans on.
Horde Shuttle — damaging unraveled targets spawns severing Threadlings, paying Unravel back into the Threadling/Strand theme.
Maligned Harvest — Stylish's weaken and Void hits trigger weakening bursts and a Void overshield, reinforcing the debuff side that lights Stylish.
To Shreds — sustained damage on severed targets unravels them and drops a Strand hotspot with Woven Mail, closing the sever → unravel loop.
Elemental Supercharger — severed-target kills with Super-element weapons grant Super energy, feeding Star-Eater's overcharge cadence.
Where it shines
- Add-dense PvE — Onslaught, Nightfalls, Legend/Master content. The swing → stow → ability-dump → Transcendent-grenade → ammo-refund loop wants packs, and it makes its own orbs, Super, and healing, so it sustains indefinitely.
- Mini-boss / orange-bar clear. A fully-stacked Gathering Light sword with max guard and lunge deletes majors; Combination Blow's escalating damage stacks on top for the ones you punch instead.
- Champion coverage — flag. Ergo Sum carries no intrinsic champion stun (swords aren't an Anti-Champion 2.0 archetype, and the perk grants no bespoke stun), and the Tablet picks above add none. Bring the stuns on your Primary/Special: Barrier/Overload/ Unstoppable frames as the content demands. Winter's Shroud slow and Stylish weaken help control champions but do not stun them — the guns do the stunning.
Mod selection (masterworked — full allocation)
| Piece | Mod · cost | What it does |
|---|---|---|
| Helmet (5/10) | Strand Siphon 1e fill | Rapid Strand weapon final blows create Orbs of Power. |
| Hands-On 3e fill | Gain bonus Super energy on melee kills. | |
| Heavy Ammo Finder 1e fill | Increases the effect of all contributions towards the Heavy ammo meter. | |
| Arms (6/10) | Heavy Handed 3e | Your powered melee final blows create Orbs of Power. |
| Momentum Transfer 2e | Causing damage with a grenade reduces your melee cooldown. | |
| Melee Kickstart 1e fill | When your melee energy is fully expended, your Armor Charge is consumed and you gain melee energy for each Armor Charge used. | |
| Chest (6/10) | Concussive Dampener 3e | Reduces incoming area-of-effect damage from combatants. |
| Strand Resistance 2e fill | Reduces incoming Strand damage from combatants. | |
| Sniper Damage Resistance 1e fill | Reduces incoming damage from combatants that are at long range. | |
| Legs (5/10) | Recuperation 1e | Replenishes health each time you pick up an Orb of Power. |
| Strand Weapon Surge 3e fill | Your Strand weapons gain a small bonus to damage while you have any Armor Charge. Your Armor Charge now decays over time. | |
| Recuperation 1e fill | Replenishes health each time you pick up an Orb of Power. | |
| Class Item (4/10) | Bomber 1e | Reduces grenade cooldown when using your class ability. |
| Powerful Attraction 2e | Automatically collects nearby Orbs of Power when you activate your class ability. | |
| Reaper 1e fill | Shortly after using your class ability, your next weapon final blow spawns an Orb of Power. |
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). Flex/loadout-dependent: live while you hold Armor Charge. - **Anti-Champion:** none intrinsic — Ergo Sum carries no champion stun; these artifact picks add none; so bring Barrier/Overload/Unstoppable on your Primary/Special frames.