Leech

Leech recovers an amount of Life, Mana or energy shield over time, relative to the damage inflicted on an enemy. Leech cares about the damage taken by the enemy, not the amount of life removed.

Mechanics

All leech mechanics act the same way for life, mana and energy shield. Examples in this article will use life, but if the character has equal statistics for a different resource (mana or energy shield), they will apply in the same way.

Whenever a character with some source of leech hits a monster a leech instance is created. A life leech instance has the following properties by default:

Each life leech instance is independent. Recovers the character's life for the Damage Dealt * #% Damage Leeched as Life up to 10% of maximum life. Recovers at a rate of 2% of maximum life per second. Recovers until the instance expires or the character is at full life. Therefore at full life all instances are removed.

Multiple leech instance stacks and apply to the character simultaneously which will lead to the total life leech rate increasing. There is no limit in number of active leech instances but the total sum of leech rate is instead limited to 20% of maximum life per second. The extra healing over that cap will be ignored. Reaching the max leech rate is quickly achieved when using an area of effect skill, a single hit that struck 10 enemies will result in 10 separate leech instances.

Leech grants recovery to the entity that hit the target. If a minion or totem with leech hits another monster the leech will grant recovery to that minion or totem only, not the character. Leech on a trap or mine has no effect, as the source of the hit has no life to recover.

Modifiers

Leech can be modified significantly through passives, support gems, and equipment. Beyond just adding various sources of leech, modifiers such as #% increased total Recovery per second from Life Leech or #% increased Maximum total Recovery per second from Life Leech can change how leech is applied to a character.

• 50% increased Maximum Recovery per Life Leech increases the default 10% of the character's maximum life pool leeched per hit/instance to 15% of the character's maximum life pool leeched per hit/instance.
• 50% increased total Recovery per second from Life Leech increases the default 2% of maximum life that can be recovered as life per second from a single instance to 3% of maximum life recovered as life per second from a single instance.
• 50% increased Maximum total Recovery per second from Life Leech increases the default 20% of maximum life that can be recovered per second from all instances combined to 30% of maximum life that can be recovered per second from all instances combined.

There are a few notable ways to affect leech:

• The of Smothering modifiers for Mapss slows life and mana leech recovery rate by 50%.
• For life leech by a skill supported by the Life Leech Support gem.
• The Baron and the Tukohama, War's Herald passive, which allow other entities to leech life to you.
• Brutal Fervour or Soul Tether allows leech instances to continue even if the character has reached full life.
• Players can become immune to being leeched from items such as Sin Trek
• Items such as Infractem prevents the user from leeching.

Leech duration

The leech recovery duration is how long in seconds a leech instance will last, based on damage dealt and character's Leech modifiers.[6]

By default a maximum of an instance is 10% of character's maximum Life, and maximum Rate is 2% of character's maximum Life per second, resulting in a maximum 5 seconds duration of a single Leech instance.

Combined Recovery Rate

The total leech recovery rate (accounting for all instances of leech) can be calculated by

total_leech_recovery_rate_per_second = max_life * 2% * instances_of_leech

where max_life can also be the character's maximum mana or energy shield.

This combined rate is subject to the total leech rate cap, which is by default 20% of the character's maximum health. This maximum is increased by #% increased Maximum total Recovery per second from Life Leech modifiers.

As such, each character only requires a certain number of leech instances before they will be recovering at their maximum rate. This maximum can be found with the below formula:

max_instances = (20% * (1 + increased_maximum_total_recovery_per_second)) / (2% * (1 + increased_total_recovery_per_second))

For a default character, this is 10 instances, but any increases or decreases from #% increased total Recovery per second from Life Leech or #% increased Maximum total Recovery per second from Life Leech will change this number.[5] If a character has too many leech instances, the extra healing will be ignored.