Tenet Cycron

Tenet Cycron is the Sister of Parvos remake of the old quest-reward Cycron, and it barely resembles its ancestor. Nobody talks about the base gun anymore. The Tenet version takes the same beam platform and turns it into one of the stronger status secondaries in the game right now.

It doesn’t ramp ammo. It ramps damage. Hold the trigger and the beam climbs from 30% to 100% of its output over 0.6 seconds, then decays back down to 30% over 2 seconds the second you let go. That one mechanic dictates how you play it. Short taps waste the weapon’s actual damage. Sustained fire on a priority target, or into a packed room, is where it earns its reputation.

Like every Tenet weapon, it also carries a Progenitor element from the Sister who dropped it, one of seven damage types determined by her Warframe. That roll matters more here than on most weapons, since the build below leans on the gun’s own elemental mods to round out a full damage spread.

How to get the Tenet Cycron

The only way to get a Tenet Cycron is to vanquish a Sister of Parvos who happens to be carrying one. There’s no vendor stock for it, full stop. Some sites will tell you Ergo Glast sells it for Corrupted Holokeys. He doesn’t. His Tenet stock is melee only (Agendus, Exec, Livia, Grigori) plus the Ferrox speargun. Want a Cycron? You’re doing the Sister grind.

You need The War Within and Call of the Tempestarii finished before Sisters even show up. From there, find a Sister-spawning statue on a Sister-eligible node and use Requiem mods or Toroids to convert a Candidate into a full Sister. When you down the Candidate, watch the Mercy prompt closely. It flashes the exact Tenet weapon she’s carrying right before you finish her off, so you’ll know if she’s holding a Cycron before you commit to the fight.

Once she’s spawned, crack her Requiem sequence the normal way, then take the fight to the dedicated Sister Confrontation node on Neptune Proxima. That means bringing a Railjack. Beat her there, pick Vanquish instead of Convert, and the weapon drops straight into your Foundry. Mastery Rank 14 is listed as the requirement, but it’s not actually enforced when you claim the weapon. Lower-MR players can still walk away with one if they can get through the fight.

None of this is fast. You’re at the mercy of RNG for which weapon a given Sister carries and which Progenitor element her Warframe assigns, so landing a Cycron with an element you actually want can take more than one full loop through the whole process. Want the guaranteed 60% Progenitor bonus instead of whatever you happened to roll? You’ll need to farm a second good copy and Valence Fuse it in, a separate grind stacked on top of the first one. If a relic or vault status comes up somewhere in your farm, check Varzia’s current rotation instead of trusting an old guide.

Stats

Riven disposition sits at 0.70x, two circles out of five. That’s low, but don’t read it as a red flag. It just means the base numbers are already doing the work a Riven would normally have to do for a weaker gun. If you do roll one, look for Critical Chance, Critical Damage, and Fire Rate, and eat negative Zoom or Recoil as the downside.

Builds

The build that keeps showing up in community setups goes full status and elemental spread instead of chasing crit. Base crit sits at 20% chance with a 1.8x multiplier, which is mediocre, and building around it means giving up slots that do more work elsewhere. Stack the Galvanized mods for scaling multishot and status, layer Toxin and Cold together for a Viral proc, add Heat from the weapon’s own kit, and let the beam’s chain and status stacking carry the damage instead.

Mod	Effect
Galvanized Diffusion	+110% Multishot. On kill: +30% Multishot for 20s, stacking up to 4x.
Galvanized Shot	+80% Status Chance. On kill: +40% direct damage per status type already on the target, for 14s, stacking up to 3x.
Pistol Pestilence	+60% Toxin damage, +60% Status Chance.
Frostbite	+60% Cold damage, +60% Status Chance. Paired with Pestilence, the Toxin and Cold combine into a Viral proc.
Primed Heated Charge	+165% Heat damage, stacking with the weapon’s innate Heat.
Primed Target Cracker	+110% Critical Damage.
Lethal Torrent	+60% Fire Rate, +60% Multishot.
Ruinous Extension	+8m Beam Range, stretching both the main hit and the chain’s reach to more targets.

For Progenitor element, Magnetic is the common recommendation. It deals bonus damage to Eximus units and Overguard, and it fills a third damage type alongside the Toxin and Heat already in the build. Toxin or Radiation show up as alternates. Valence Fuse toward the guaranteed 60% bonus once you land a second good copy, and once the weapon hits rank 40, the Elemental Vice mod lets you swap that element freely instead of committing to one forever.

For the arcane slot, Secondary Merciless is the common pick. It’s on-kill stacking damage that doesn’t need a headshot trigger, which matters here because the beam makes clean headshots awkward to land in the first place. Running a crit-leaning variant instead? Secondary Enervate shows up as an alternative, stacking crit chance on hit.

Reviewed September 2026.

Pros and Cons

This is a low-maintenance pick for anyone running long Steel Path survival, defense, or disruption where ammo restores get old fast. It rewards holding the trigger down on priority targets and packed rooms rather than tap-firing, so it suits a more patient playstyle than a spray-and-forget beam weapon. Already running a Sister farm for another weapon? Grab a Cycron while you’re there. If the Railjack and Requiem grind is the only thing standing between you and this gun, be honest with yourself about whether the payoff is worth that specific chore, because there’s no shortcut around it.

Related

• Best Steel Path weapons
• Torid
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