Lethality is one of the most important bonus stats that a League of Legends player can achieve while using a burst AD champion. Lethality was introduced in 2017 as a new bonus statistic in League of Legends. It was added as a replacement for flat armor penetration. #LeagueofLegends #FridayGamingYep, lethality in 2017 is broken :D https://t.co/0ejWoQzZrt— uSpotGaming (@uSpotGaming) February 24, 2017This stat is extremely useful for AD champions as it allows them to deal heavy damage to enemies. It reduces the amount of armor an opponent has when attacked. However, it is an "effective reduction" and not a true reduction in armor.How does Lethality work in League of Legends?Image via Riot Games - League of LegendsLethality works by reducing the opponent’s armor while dealing damage. It somehow provides a boost to the champion's physical damage, resulting in a heavy reduction in the opponent's armor effectiveness. Its effect is, however, restricted to a single champion and not the entire team. There are other items, such as Black Cleaver, that reduce armor for everyone in a team.Image via gamepediaHow to calculate LethalityLethality works as a booster to flat armor penetration. It is a scaling stat that starts out relatively small and builds throughout the game. As a result, the armor stat does not lose its long-term effectiveness as a match progresses. The formula by which flat armor penetration is calculated in League of Legends is:Flat Armor Penetration = Lethality x (0.6 + 0.4 x level % 18)From the formula, it can be understood that, at level 1, a player gets just a bit more than 60% of the lethality stat as direct flat armor penetration. However, at level 18, the player gets the full bonus lethality stat as flat armor penetration.lethality stat increase on ymgb duskblade and eon aswell pic.twitter.com/f4iEfvPeaN— GORMOTTI (@yasuchu__) July 6, 2017The amount of lethality a champion receives rises with an increase in its level. To avoid all sorts of in-game calculation complexities, Riot has enabled a simple feature by which a player can keep a check on their champions' lethality simply by hovering over them.Lethality vs Armor PenetrationLethality is flat while Armor Penetration is based on a percentage. Lethality can be denoted as "negative armor." The amount of lethality a champion possesses is the amount of armor removed from his enemy. League of Legends Lethality shows one kind of armor mitigation stat. There are also other kinds, such as:Fixed Armor ReductionFixed armor reduction is similar to lethality but it gets applied to all allies, not just a single champion. It reduces the opponent's armor by a fixed amount and, it stacks additively.Fixed Armor is particularly effective against targets with a small amount of armor or no bonus armor. It should be avoided against teams with a large number of tanks as global fixed armor reductions are usually low and generally help to defeat squishy champions.Percentage Armor ReductionPercentage armor reduction decreases an opponent’s armor for all of the allies by a percentage. Unlike fixed armor reduction, it stacks multiplicatively.For example, if a player has one item with 30% armor reduction and another has 20% reduction, and their original armor was 200, their final armor would be reduced to (100-30)% * (100-20)% * 200 = 112.Percentage Armor reduction is a good stat to build if the enemy team has multiple tanks.Percentage Armor PenetrationPercentage armor reduction is not applied to allies but only to a single champion. It stacks multiplicatively.AD Carries hugely benefit from this stat, especially marksmen that deal high physical damage themselves. Additionally, as a percentage armor reduction modifier, it’s most effective against tanks.Percentage Armor Bonus Penetration: It affects only the bonus armor obtained through items and runes, but it does nothing to a champion’s base armor. This is highly ineffective against glass cannons.League of Legends Lethality and Damage Reduction OrderWhen multiple armor debuffs are applied, they are applied in the following order:Flat Armor ReductionPercentage Armor ReductionPercentage Armor PenetrationLethalityAs Lethality in League of Legends is applied at last, it cannot reduce an enemy's effective armor below 0.Best Lethality Items in League of Legends Season 11Some of the best League of Legends Items and Runes for Lethality (Image via gamepedia)Some of the best Lethality items in the current meta are:Duskblade of DraktharrEclipseEdge of NightSanguine BladeThe CollectorProwler’s ClawSerpent’s FangSerrated DirkUmbral GlaiveYoumuu’s Ghostblade@JPflygon Duskblade of DraktharrTeamfight multikill3200 gold+55 Attack Damage+18 Lethality+25 Ability Haste Dusk: Attacking an enemy champion deals 50-150 (lv 1-18) (+30% bonus Attack Damage) additional physical damage and slows them by 99% for 0.25 seconds (15 second cooldown— Marcio Gonsalez (@MarcioJG1) September 29, 2020Champions that benefit from LethalityAn AD build of Pyke featuring Lethality (Image via Mobafire)Assassins and Fighters are the breeds of League of Legends champions that benefit from Lethality. Some of the best champions to peddle Lethality are:ZedPykeJarvan IVDariusHow to counter LethalityZhonya’s Hourglass is a good item for countering Lethality (Image via Riot Games)Lethality is generally used by players to one-shot squishies. Builds with items that grant armor in addition to damage, such as Death’s Dance or Zhonya’s Hourglass, counter most League of Legends lethality stacks.