Confused about "increased life leeched per second"

I've been doing some leech-related calculations for my character and I stumbled upon something I do not quite understand from both the wiki and GGG forum posts.

I know that every hit I deal creates a "life leech instance" for my character that continuously restores life to me. The amount of life restored by this instance is given, in the absence of other modifiers, by:

life_leeched = damage_dealt * (life_leech_amount / 100)

where damage_dealt is the damage the enemy takes (after all mitigation), and life_leech_amount is the sum of all applicable "X% of Y damage leeched as life" modifiers on my character.

The duration of this life leech instance is given by:

leech_duration = life_leeched / (max_life * 0.02)

where max_life is the maximum life of my character. This means that, by default, every instance of life leech heals me for 2% of my maximum life per second, until it heals a total of life_leeched life.

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What I am confused about is the modifier "X% increased life leeched per second". Both the wiki, Mark_GGG, and GGG_Neon insist that this modifier does not change the duration of the leech effect. If it does not change the duration, and it changes the recovery rate, then it must also increase the total amount of life I recover for each hit!

The confusing quote from Mark is:

"

Mark_GGG wrote:

Each time you hit a thing and deal damage you can leech from, you'll create add one leech effect to yourself.
The rate of that leech effect is 2% of max life per second, increased by your "increased life leeched per second" modifiers. E.g. 100% increase would mean each leech effect is leeching at a rate of 4% of maximum life per second.
The duration of each leech effect is simply how long it has to last to recover the correct amount of life, given this fixed rate, i.e. leech_duration = life_leeched / leech_rate

If you have modifiers that give you increased life leeched per second, these apply here to make you actually get more per second, for the same duration.

Mark here seems to contradict himself. He, as I understand the post, gives the calculations:

leech_rate = max_life * 0.02 * (1 + increased_life_leeched / 100)
leech_duration = life_leeched / leech rate

Obviously given these relationships, leech_duration is affected by increased_life_leeched, which Mark contradicts in the next sentence!

So what exactly does the "X% increased life leeched per second" do? Does it affect

• The duration of the life leech effect?
• The amount of life restored per second by the life leech effect?
• The total amount of life restored by the life leech effect?

Clearly it can not affect only one of the above, since the three are proportionally related.

Can someone give an accurate formula for leech_rate, leech_duration, and life_reached; given that we know damage_dealt, life_leech_amount, and increased_life_leeched? (It should hold that life_leeched = leech_rate * leech_duration.)

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Secondary question: if "X% increased life leeched per second" does indeed affect the total amount of life leeched, does it also work this way when the leech is instant (such as with Bloodseeker)? This seems very counter-intuitive to me!

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N.b.: I know about the maximum leech rate (20% of maximum life per second). This is not at all what this post is about. Simply assume that I do not reach this cap.

Leech Rate used to reduce Leech effect duration, but the function of Leech rate modifiers was explicitly changed to prevent this negative side-effect. 2.0.0. patch notes:
"Previously, we had modifiers for "increased (or reduced) Life/Mana Leech rate". These did two things: They increased the amount of Life/Mana you're gaining per second for each leech effect and they reduced the duration of each leech effect, such that the total life/mana gained over the duration remained the same. All such modifiers have now been changed to "increased (or reduced) Life/Mana Leeched per second". This still increases the value of Life/Mana you're gaining per second for each leech effect, exactly as it did before. It no longer affects duration of the leech effects, meaning you'll gain more total life/mana from each one as a result."

This is conform with Mark's final comment in the quote, which explicitly states that Increased Life Leeched would apply after duration was determined.

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Instant effects do not have a per-second value to increase. Increased Life Leeched has no effect on instant Leech, as such.

Does this indeed mean that "X% increased life leeched per second" makes me leech more total life per hit (assuming leech is not instant)?

Example 1:
I hit an enemy for 4000 damage. I have 1% of damage leeched as life. I have 2000 maximum life.
I should leech 4000 * 0.01 = 40 life over a period of 40 / (2000 * 0.02) = 1 second. (At a rate of 40 life/second, obviously).

Example 2:
As above, only now I have 50% increased life leeched per second.
Does this mean that with the same hit, I now leech for 1 second at a rate of 60 life/second, i.e. that I will leech 60 life total?

Do I understand it right?

Yeah, it's a straight multiplier to your total Life gained. It's really good for casters, makes the smaller amounts of Life Leech perfectly servicable. Attackers get so much Leech that they don't really need it as much, but getting it for free from Leech passives is nice.

Wait a sec, this means that "20% increased life leeched per second" from Vitality Void also increases the amount of life gained from leech from spells (assuming you have some source of spell damage leech, since Vitality Void only provides attack leech).

Neat.


[Edit] The new Vaal Pact doubles the amount of life you leech. Also neat.