Leech

"Life Leech" redirects here. For the support gem, see Life Leech (support gem). For the passive skill, see Life Leech (passive skill).

"Mana Leech" redirects here. For the support gem, see Mana Leech (support gem).

Leech restores over time an amount of life, Mana or Energy Shield relative to the damage inflicted on an enemy.

Leech mechanics in The Awakening

In the The Awakening expansion the leech mechanics were changed with the goal to make it harder to leech against a single enemy. Earlier the leech recovered at a constant rate, this method does not take into account how many enemies that were hit by the skill. The leech mechanic was therefore changed to vary how fast the leech recovered depending on how many enemies were hit; with more targets hit by the skill the faster the character healed from the leech.

The total amount of life or mana leeched without Vaal Pact can be described as

HP(t) = r * t

where r is the leech recovery rate and t is the time. The leech recovery rate, r, varies depending on how many enemies have been hit and how many times the enemies have been hit.

Recovery rate

Values of the Base Leech Rates

Symbol	Value	Description
q	2 % 2 %	Base Life Leech Rate Base Mana Leech Rate
qmax	20 % 20 %	Base Maximum Life Leech Rate Base Maximum Mana Leech Rate

The leech recovery rate r is given by

r = p * n * q * (1 + m)

where p is the character's maximum life (for life leech) or mana (for mana leech), n is the number of active leech instances, q is the Base Leech Rate and m is the sum of all the #% increased (or reduced) Life/Mana Leeched per second modifiers.

There is a upper limit of the leech recovery rate which is defined as

r_max = p * (q_max + m_max)

where q_max is the Base Maximum Leech Rate and m_max is the sum of all the #% of maximum Life/Mana per second to maximum Life/Mana Leech rate modifiers.

If r > r_max those values will be substituted with r_max. The total amount of active leech instances allowed, n_tot, to not exceed the maximum recovery rate is

n_tot = (q_max + m_max) / (q * (1 + m))

Derivation of ntot
Find the amount of instances that gives the maximum leech recovery rate: r = rmax p * n * q * (1 + m) = p * (qmax + mmax) solving for n yields the total amount of active leech instances allowed ntot = n = (qmax + mmax) / (q * (1 + m))

Leech duration

The leech recovery duration for each instance in seconds is given by

t_dur = d * l / (p * q)

where d is the damage inflicted on the enemy, l is the total amount of leech. The leech duration is independent on other leech instances.

To be able to sustain the maximum recovery rate, r_max, against a single target the total amount of instances allowed needs to be active at all times, n_tot. The attack time between each hit, t_att, needs to be

t_att ≤ t_dur / n_tot

Modifiers

Modifiers that alters the leech recovery rate increases the value of Life/Mana you're gaining per second for each leech effect. However, it does not affect the duration, t_dur, of the leech effects, meaning that more total life/mana will be gained from each leech instance as a result. This also implies that by increasing the Life/Mana Leeched per seconds gives a larger total of life leeched compared to Vaal Pact.

There are only a couple of ways for these factors to be altered, besides the passive tree:

• The of Smothering modifier for maps slows life and mana leech recovery rate by 50%.
• For life leech by a skill supported by the gem.
• Vorici's master modifier also offers #% increased Life Leeched per second.

Examples

When using skills such as linked with several enemies can be hit at once. The leech rate will vary considerably depending on how many enemies are hit. The character used in the following examples have the following stats:

p = 5000 maximum life.

d = 1000 damage taken by the enemy.

l = 1 % life leech.

1 enemy hit

n = 1 leech instance/enemy. m = 0% increased Life Leeched per second. mmax = 0% of maximum Life per second to maximum Life Leech rate. The recovery rate is: r = n * p * q * (1 + m) = 1 * 5000 * 0.02 * (1 + 0) = 100 HP/sec Make sure that the recovery rate doesn't exceed the maximum recovery rate which is rmax = p * (qmax + mmax) = 5000 * (0.2 + 0) = 1000 HP/sec The limit has not been exceeded, meaning that no substitution is necessary. The time it takes to recover the total amount of life leeched is tdur = d * l / (p * q) = 1000 * 0.01 / (5000 * 0.02) = 0.1 seconds which gives the total life leeched HP(tdur) = r * tdur = 100 * 0.1 = 10 Life

5 enemies hit at once

n = 5 leech instances/enemies. m = 0% increased Life Leeched per second. mmax = 0% of maximum Life per second to maximum Life Leech rate. The recovery rate is: r = n * p * q * (1 + m) = 5 * 5000 * 0.02 * (1 + 0) = 500 HP/sec Make sure that the recovery rate doesn't exceed the maximum recovery rate which is rmax = p * (qmax + mmax) = 5000 * (0.2 + 0) = 1000 HP/sec The limit has not been exceeded, meaning that no substitution is necessary. The time it takes to recover the total amount of life leeched is tdur = d * l / (p * q) = 1000 * 0.01 / (5000 * 0.02) = 0.1 seconds which gives the total life leeched HP(tdur) = r * tdur = 500 * 0.1 = 50 Life

11 enemies hit at once

n = 11 leech instances/enemies. m = 0% increased Life Leeched per second. mmax = 0% of maximum Life per second to maximum Life Leech rate. The recovery rate is: r = n * p * q * (1 + m) = 11 * 5000 * 0.02 * (1 + 0) = 1100 HP/sec Make sure that the recovery rate doesn't exceed the maximum recovery rate which is rmax = p * (qmax + mmax) = 5000 * (0.2 + 0) = 1000 HP/sec The limit has been exceeded, therefore the recovery rate needs to be changed to r = 1000 HP/sec. The time it takes to recover the total amount of life leeched is tdur = d * l / (p * q) = 1000 * 0.01 / (5000 * 0.2) = 0.1 seconds which gives the total life leeched HP(tdur) = r * tdur = 1000 * 0.1 = 100 Life

Types of Leech

There's several types of leech that specializes on certain types of skills. Some leech types only works for attacks, others only works with elemental damage or physical damage. If there is specialization it will be defined in the modifier.

Generally the leech modifiers follow this template:

#% of X Y Damage Z Leeched as Life/Mana

Where X can be:

• Physical/Fire/Cold/Lightning/Elemental/Chaos

Y can be:

• Attack/Spell

and Z can be:

• Dealt with Weapons

Note that if X, Y or Z are not specified it means that it applies to all those types.

Examples

• and has the mod #% of Damage Leeched as Life/Mana implying it works for all types of skills that hits a target.
• also has the mod #% of Damage Leeched as Life/Mana, granted the enemy already is cursed.
• The notable passive Soul Raker grants the mod #% of Physical Damage Dealt with Claws Leeched as Life specifying it works for only Physical damage dealt by a Claw, this implies that this passive only works for Attacks because Spells are separate from the weapon.
• The notable passive Lust for Carnage grants the mod #% of Physical Attack Damage Leeched as Life specifying it works for Physical Attacks. All types of weapons can make use of this notable, however not Spells.

Passive skills

There are passive skills that grant passive leech or bonuses to leech.

Life Leech

There are passive skills that grant passive life leech or bonuses to life leech. Template:Passive table

Minion Life Leech

These passive skills grant life leech for minions.

Miscellaneous

These keystone passive are related, but don't add any life leech as a percentage of physical damage.

The Vaal Pact Keystone will allow life leech to apply immediately at the cost of losing life regeneration. Ghost Reaver applies life leech to energy shield instead of life.

Mana Leech

There are passive skills that grant passive mana leech or bonuses to mana leech.

Immunity to leech

A player can become immune to being life leeched from by enemies through allocating the Bloodless notable passive skill.

Immunity can also be achieved by equipping certain unique items.

Cannot Leech

Certain unique items prevent the user from leeching life and/or mana.