Assist

An Assist is the action of helping an allied champion kill someone. You can either score an assist by hitting the champion in the last 10 seconds before his death, or by contributing passively during this period of time.

Scoring an assist will grant a certain amount of gold. Gold equal to 58.33% of the amount the killer receives is put in a pot which is split equally among all champions who scored an assist.

Secondary system
Champions also gain assists on kills if they contributed to the battle via active abilities but did not deal damage. In addition, assists will be granted if the champion debuffed an enemy but they were immune to the damage. Certain effects like blind, reveal, and attack speed slows will not grant assists.

Additionally, assists can be scored by passively supporting a champion that contributed to the kill, e.g. by healing an allied champion.

Items benefitting from assists

 * Unique passive - Your champion gains +5 damage per stack, receiving 2 stacks for a kill or 1 stack for an assist. This effect can stack 20 times; you lose a third of your stacks if you die. At 20 stacks, your champion's movement speed is increased 15%. 1369 Gold.
 * Unique passive - Your champion gains 8 ability power per stack, receiving 2 stacks for a kill or 1 stack for an assist. This effect can stack 20 times; you lose a third of your stacks if you die. At 20 stacks, your champion's cooldowns are reduced by 15%. 1235 Gold.
 * Unique passive - Your champion gains 32 health per stack, receiving 2 stacks for a kill and 1 stack for an assist. This effect can stack 20 times; you lose a third of your stacks if you die. At 20 stacks, your champion takes 15% less damage. 1275 Gold.
 * Passive - Permanently gain 3.5 health and 0.1 health regeneration per 5 seconds per minion kill. Champion kills and assists grant 35 health and 1 health regeneration per 5 sec. Bonuses cap at +350 health, and +10 health regeneration per 5 seconds. 3000 Gold.

Skills benefiting from assists

 * (Active): Akali moves through the shadows to quickly strike her target and deal magic damage. Akali gains an Essence of Shadow once every few seconds up to a total of 3, affected by cooldown reduction. The time to gain a charge doesn't count when at maximum charges. Additionally, Akali gains an Essence of Shadow for a kill or an assist.
 * (Active): Evelynn removes all slows affecting her and gains bonus movement speed for 3 seconds. Champion kills and assists refresh Dark Frenzy's cooldown.
 * (Innate): After a kill or an assist, Katarina gains 25 gold and her cooldowns are reduced by 15 seconds.
 * (Active): Increases Master Yi's movement speed by 40% and attack speed for a few seconds, as well as making him immune to any slow effects. Additionally, killing a champion refreshes all of Master Yi's Abilities. Assist refreshes all abilities by half.
 * (Active): Tristana fires at the ground to propel herself to a target location, dealing magic damage and slowing surrounding units by 60% for 2.5 seconds when she lands. On kills or assists, Rocket Jump's cooldown resets.
 * (Active): Fiora gains additional attack speed for 3 seconds. Each autoattack or Lunge she lands during this time increases her movement speed for 3 seconds, stacking up to 3 times. Killing a champion refreshes the cooldown on Burst of Speed. Assists reduce the cooldown by half of the base amount.
 * (Innate): On champion kill or assist, Varus gains 40% attack speed for 6 seconds. On minion kill, Varus gains 20% attack speed for 3 seconds.