Modifies the Energy cost of Warframe abilities. Energy cost cannot be reduced to below 25% of its initial value.
> Abilities cost |AMOUNT|% of their initial value
> Channeled Abilities cost |AMOUNT|% of their initial value. Ability Duration affects the cost.
—In-game Description
Ability Efficiency linearly affects the energy cost of Warframeabilities. All Warframes have a base Ability Efficiency of 100%; Ability Efficiency over 100% indicates a reduction of ability cost while Ability Efficiency below 100% indicates an increase in ability cost. Ability Efficiency cannot go below 25%. The Arsenal will not display an Ability Efficiency above 175% because abilities cannot consume less than 25% of their base costs, but the Ability Efficiency stat itself is not capped.
When accounting for Ability Efficiency, ability energy costs can be calculated:
Channeled abilities drain energy at a specified rate. Ability Efficiency affects the energy drained at each tick as expected, but because Ability Duration affects the amount of time between these ticks, the formula for effective Ability Efficiency for channeled abilities is as follows:
In the case of Ability Duration under 100%, Ability Efficiency above 175% is also taken into account, even though not depicted in the Upgrade-Menu. The final drain still cannot go below 25% of its base value. (See the graph on the right for examples.)
The in-game energy bar display is rounded down to the nearest whole number, but the costs of the abilities are not. This results in the discrepancies in the apparent cost of abilities with Ability Efficiency mods. For example, an ability with 25 energy base cost will cost 17.5 energy with maxed Streamline (+30%). If this ability is used multiple times in a row, it will appear to cost 18 energy, then 17 energy, then 18 energy, then 17 energy and so on.
Energy Drain for Toggled Abilities[]
Some abilities are toggled on and last until the user turns them off or runs out of energy, such as Hildryn's Haven or Chroma's Spectral Scream. Energy drain for these toggled abilities depends on both Ability Efficiency as well as Ability Duration. See the related section for a full explanation.
Other Behavior[]
Some Warframe abilities do not cost energy to cast, thus ability efficiency has a unique effect on these abilities:
Garuda slashes herself with her talons as she spins into the air, sacrificing up to 50% of her maximum Health to cleanse all status effects and restore up to 18% / 22% / 30% / 40% of her maximum Energy capacity. Garuda cannot reduce her health below 2 health points using Bloodletting.
Health cost is 50% of Garuda's maximum HP, including mods.
Total Energy Gain = Base Energy Gain ÷ (2 - Ability Efficiency).
Bloodletting can be cast if Garuda has less than 50% of her maximum HP remaining, but will only restore energy proportionate to the amount of HP sacrificed. For example, if she has 25% of her health left (or 50% of 50%) when Bloodletting, the energy gain will be halved.
Cannot be cast if Garuda has 2 or less health points.
This ability does not trigger health damage into energy conversion mods like Rage or Hunter Adrenaline.
This ability gains no benefits from increasing health. Having lower max health allows flat HP regeneration such as health orbs or Oberon's Renewal to generate more energy more quickly.
Synergizes with Blood Altar's continuous healing to give Garuda a near infinite supply of energy.
Despite sacrificing HP, Bloodletting is an effective way of shedding off any harmful status effects (especially slowing effects and DoT procs from Slash and Toxin damage), possibly improving her survivability better than not removing the procs.
Bloodletting is a powerful ability to combine with Helminth-infused toggled abilities that constantly drain energy, the most notable being Sevagoth's Gloom as it provides Garuda with another self-healing ability besides Blood Altar to constantly regenerate her energy reserves.
The Gloom and Bloodletting combo makes Garuda viable at completing Steel Path missions alone, including missions not normally frequented by players such as the Rathuum nodes and the Zealoid Prelate battle in Deimos.
Seeking Talons also synergize extremely well with this build as the damage-over-time of her quills also triggers Gloom healing and, subsequently, powers Bloodletting. The quills' homing ability also offers little chance for enemies to escape and can even track and hit hiding enemies, ensuring Garuda can be healed by Gloom as long as they stay within the aura.
Molt Reconstruct can work as a stand-in for Gloom's regeneration by allowing any energy spent to heal a large portion of Garuda's health. Often healing her to full in a single cast.
Bloodletting itself will not restore health however, as it does not expend any Energy.
Equipping Blood Forge and using Bloodletting allows Garuda to quickly reload otherwise slow-reloading weapons (such as the Strun, Nagantaka, Tenet Envoy and Kuva Zarr) and increase their overall DPS potential. It comes at the risk of getting struck while already losing her Health to reload, thus she should consider safeguards such as a nearby Blood Altar or equipping Quick Thinking and/or Gladiator Finesse, the mods accounting for her replenished Energy while using Bloodletting.
Slotting Azure Archon Shards for extra Energy while also equipping Quick Thinking will make Garuda deceptively durable due to the resulting increased efficiency of regaining Energy via Bloodletting.
Slotting Azure Archon Shards for extra Armor instead of extra Energy grants Garuda more effective hitpoints since Quick Thinking benefits from Armor.
If a Garuda player wishes to take advantage of the reworked passive to further amplify damage output, Helminth can replace Bloodletting with another damage-related self buff ability, such as Xaku's Xata's Whisper or Mirage's Eclipse, as these abilities synergize well with the damage buff and Garuda's own Seeking Talons, while still maintaining self-survival options with Dread Mirror and Blood Altar.
In exchange for losing this ability to generate Energy, Garuda can equip Rage or Hunter Adrenaline so she gains Energy while taking damage - which will be offset by a nearby Blood Altar.
Launch a probe that converts Health and Energy Orbs into Universal Orbs that provide both, and ammo pickups into Universal Ammo Pickups. The probe shocks enemies in close proximity. Each electrocuted foe reduces other ability cooldowns by one second.
Hold to imbue the next ability cast with Electricity.
Misc:
15 m/s (probe speed) 3 s (probe duration) Electricity and imbued elemental status proc per second 0.5 s (halt delay) 25 HP/EP (Universal Orb restore) 1x (Universal Ammo restore)
Lavos launches an advanced alchemical apparatus toward the direction of the aiming reticle. The Transmutation Probe is an invulnerable floating device that travels at a speed of 15 meters per second, lasting for 3 seconds, as it emits a field of electrical currents spanning a 3 / 4 / 5 / 6 meter radius. Enemies within the electric field receive 100 / 150 / 200 / 250Electricity and 100 / 150 / 200 / 250 Imbued Elemental damage and status effects per second; for each enemy electrocuted, 1.5 seconds is removed from the active cooldowns on Lavos' other abilities. Press the ability key again (default 3 ) after the ability has been active for at least 0.5 seconds, to hold the probe's position at its current location. Casting Transmutation Probe triggers a cooldown of 10 seconds after the probe expires.
Electric field does not require enemies to be in direct line of sight to apply damage and status effects.
The probe's duration timer is shown on the ability icon and must expire before the ability cooldown begins.
Therefore, Transmutation Probe cannot reduce its own cooldown timer.
Each enemy shocked may only reduce Lavos' other active ability cooldowns once per probe, not repeatedly while they stay in the field.
Although appearing as a floating object, the probe is affected by gravity and will drift down to the lowest available horizontal surface as it travels.
The probe collides with solid obstacles in the environment, stopping its movement prematurely.
Halting the probe by pressing the ability key again will stop the probe's movement permanently until it expires.
Standard Pickups on the ground that pass through the probe's field, including Health Orbs, Energy Orbs, and Ammo Packs, are transmuted into special Universal variants; Universal Orb provides 25Health and Energy points, while Universal Ammo Pack replenishes 1xAmmo Pickup for all equipped weapons.
Universal pickup restore values are not affected by mods.
Hold down the ability key (default 3 ) to add Electricity damage to Lavos' mixing vial at no cost, as the Imbued Elemental damage type for his next ability cast.
Transmutation Probe reduces all active cooldowns on Lavos' other abilities, including Helminth Subsumed abilities, for each enemy it electrocuted. If enemies were electrocuted while Lavos' other abilities are in use, but their cooldowns have not yet begun, the cooldown reduction is carried over to the cooldowns.
Electricity status effects inflicted on enemies by Transmutation Probe enhance Catalyze's damage.
Can be cast and halted while moving or in midair. The probe will descend in a diagonal glide to the ground.
Casting Transmutation Probe is an upper-body animation that allows movement while restricting other actions. Holding the probe's position does not play an animation on Lavos.
Nullifier Crewman and Isolator Bursa bubbles are considered solid objects that block Transmutation Probe from traveling through them.
Lavos visually summons the Transmutation Probe from his right hand as he throws the probe forward. The probe remains in perpetual motion rotating its upper half counterclockwise and lower half clockwise, while emitting two jets of gas for propulsion. Electrical currents forming the transmutation field encircle the probe in a similar pattern to electrons orbiting an atom. While in motion, the probe pushes a large spiraling energy force.
When a different element is imbued, the electrical currents adopt different appearances and energy particles representing the additional elemental damage type.
Transmutation Probe, gas jets, electrical currents, elemental particles, and energy force are affected by Lavos' Appearance colors.
Universal Orb visually appears as a pulsating, rippling orb with a diluted blue outer layer enveloping a red inner core. Universal Ammo Pack shares the same model as those produced by Protea's Dispensary.
Arcane Helmets also reduce (or increase) ability costs linearly based on the percentage shown on the helmet. This was removed following the 13.2.3 Patch. The following helmets used to affect Ability Efficiency:
Streamline (+30%). If this ability is used multiple times in a row, it will appear to cost 18 energy, then 17 energy, then 18 energy, then 17 energy and so on.
Hildryn's 
Haven or 
Chroma's 
Spectral Scream. Energy drain for these toggled abilities depends on both Ability Efficiency as well as Ability Duration. See the related section for a full explanation.
Strength:N/A
Duration:N/A
Range:N/A
Efficiency:
10
Electricity damage per second)
Pax Bolt, and the positive Ability Efficiency Arcane Helmets stack additively. Stacking with Trinity Meridian Helmet or Ash Scorpion Helmet does not appear to follow this formula; this suggests stacking is different when you have a helmet that reduces Ability Efficiency.
