EDIT 24 Apr 2020: yesterday’s update has changed Sustainment radically. This guide is no longer valid.
Early tests suggest the following changes:
- Infusion works with Sustainment now, so you can get life steal even with kinetic weapons
- Life steal amount is based on actual damage dealt now, not the weapon’s base damage
- Forceful Expression, bonus element anointments, DOT still don’t give life steal
Original post (now obsolete):
Questions about this pop up a lot, and I’m curious too because it’s my only healing source and I want to understand better how it works so I can make the most of it and avoid anything that doesn’t work. So… testing time. May be updated, corrections are welcome.
First things first: yes, it actually is 4% per rank for up to 20%. It’s just not calculated in a way one would expect (and not how the description suggests). For my examples, I’ll assume we have 5/5 = 20%.
What qualifies for life steal
Sustainment is triggered by elemental attacks, including:
- elemental guns
- elemental grenades
- action skills
- orbs from Do Unto Others or Remnant
- melee with Illuminated Fist and/or Blitz
- enemies hit by an elemental explosion from radiation or Catharsis
- elemental spike/nova shields
- even though it’s called “life steal”, it doesn’t matter if you hurt their health, shields, or armour. The only thing that counts is that you hit something with an elemental attack (even your vehicle).
Sustainment is not triggered by:
- status effects (damage over time)
- non-elemental attacks, even with Infusion or Forceful Expression. These skills have no effect on Sustainment at all.
What it does
When you hit an enemy with an elemental attack, Sustainment takes the base damage stated on the card, and heals you for 20% of that.
Healing output is affected by:
- +100%, +250%, +300% gun damage anointments
- Dahl’s semi-auto mode damage bonus
- some weapons can be charged to increase damage (Proton Rifle/Melter: up to 2x, Ion Cannon: up to x2.25). The Antimatter Rifle always deals 2x the damage stated on the card. Healing output is scaled with all of these.
It’s not affected by:
- +125% splash damage anointment
- +125% against badasses anointment
- elemental multipliers – what element you use against what enemy type is irrelevant. If you want some quick healing, don’t bother switching to a weapon with matching element – it makes no difference if you hit flesh with fire or shock.
- any other elemental bonuses (Infusion, Forceful Expression, bonus elemental damage anointments…)
- Guardian Ranks
- most skills
- critical hits
Say you’ve got a 1000 dmg Maliwan pistol with fire and shock. Say you’ve got a ton of skills and bonuses and elemental multipliers and whatnot, and you crit a Psycho with fire for 7540 damage or whatever. Amount healed is 1000 × 20% = 200. This is why Sustainment may seem “broken” because it heals far less than expected (and truth be told, judging by the description’s wording it is broken).
Now switch to shock and you don’t crit and damage dealt is maybe 1360. Amount healed is 1000 × 20% = 200. So for healing, use any element against anything, crit or don’t, it doesn’t matter.
For action skills, calculation is based on base damage as stated in the description. For melee, base damage is 1338 at level 50, so Illuminated Fist will heal 1338 × 20% = 268.
However if you hit several enemies at the same time, e.g. with splash damage or Phasecast, every hit counts.
Ties That Bind
Sustainment’s natural ally. When hitting one of the linked targets, all others receive an elemental attack with base damage = 35% of damage dealt to the first target. The element is Amara’s action skill element, however again, it doesn’t matter for healing which one you use.
Since it’s based on actual damage dealt to the first target, now all damage bonuses count, including Guardian ranks, elemental bonuses, critical hits, etc. – greatly increasing healing potential. It also means that you can use a non-elemental weapon like a Jakobs gun; you won’t be healed from the target you hit, but you will be healed from all linked targets.
Skills affecting Sustainment
There are a few exceptions to the rule:
- Wrath: Increases gun damage, healing is increased accordingly.
- Dread: same.
- Jab Cross: Gun damage bonus also increases healing.
- Blitz: the 100% bonus doesn’t increase healing, however when procced it has a hidden multiplicative bonus on top of that (×1.5 to all melee damage at level 50), which also increases healing.
- Reverberation increases damage to every enemy hit in one attack, healing is scaled accordingly.
- A Remnant orb can carry a sh!tload of excess damage regardless of points invested, which is also used for healing. even 1 point here can be pretty substantial.
- Overkill damage from the Guardian reward also increases healing.
I don’t know if Samsara’s gun damage bonus increases healing too. I find it impossible to test because it constantly regenerates health at the same time.
Other skills I’ve tested with no effect on Sustainment:
- Forceful Expression
- Personal Space
- Arms Deal
- Find Your Center
- Do Harm
- Laid Bare
edit 20 Jan 2020: moved Dread to skills affecting Sustainment. It definitely works now but I’m fairly sure it didn’t 2 months ago (hotfixes often change how skills work). Anyway, Dread does affect Sustainment.