Luck (幸運 Kōun) is a core character statistic that serves a variety of functions. As with the other core stats, it has a chance of increasing each time a character levels up.
Overview
Luck is a stat that varies in it's formula and it's uses from game to game, a lot more than the other core stats in Fire Emblem. Generally however, it determines Hit Rate and Avoid, but to a lesser extent than Skill/Dexterity would. Most importantly however, the stat it used to determine Critical Evade, which will, as the name implies, reduce a units chance of being hit by Critical hits. It also has a lot of unique interactions with weapons as they appear across games, for example the trigger rate of the Devil weapons is determined by a users Luck stat.
Game-specific Luck Effects
Fire Emblem: Shadow Dragon and the Blade of Light
Luck does not affect Hit Rate at all in this title.
Luck only boosts your Avoid against Magical attacks specifically (Luck)%.
There is also no Critical evade stat in this title, therefore Luck does not boost it.
It does boost the rates of Critical hits however ([Skill + Luck]/4)%.
Fire Emblem Gaiden
Luck remains very similar to Shadow Dragon.
Luck's boost to Magical Avoid is now (Luck/2)%.
Fire Emblem: Mystery of the Emblem
Luck does not affect hit rates and no longer boosts critical hit rates.
Luck's bonus to Avoid is ([Skill + Luck]/2)%.
Luck's bonus to Critical Evade is (Luck)%.
Fire Emblem: Genealogy of the Holy War
Luck affects purely Avoid when it comes to core stats ([Attack speed × 2] + Luck)%.
Ulir blood gives a 30% boost to luck growth and Baldr and Bragi blood give a 10% boost to luck growth.
Fire Emblem: Thracia 776
Luck now affects Hit Rate ([Skill x 2] + [Luck])%.
Luck's bonus to Avoid is ([Attack speed × 2] + Luck)%.
Luck's bonus to Critical Evade is (Luck/2)%.
Luck also for the first time has an effect on a unit Skill, in this case Miracle.
Fire Emblem: The Binding Blade
Luck affects Hit Rate rate in this title, granting to bonus of [(Skill x 2] + [Luck/2])%.
Luck's bonus to Avoid is ([Attack speed × 2] + Luck)%.
Luck's bonus to Critical Evade is (Luck)%.
Fire Emblem: The Blazing Blade
Luck remains entirely unchanged from The Binding Blade. However the formulas for Hit Rate, Avoid, Critical Hits and Critical Evades do change due to other factors.
Fire Emblem: The Sacred Stones
Luck once again stays unchanged from the prior two Game Boy Advance titles, but like before the formulas for Hit Rate, Avoid, Critical Hits and Critical Evades do change due to other factors.
Fire Emblem: Path of Radiance
Luck affects Hit Rate rate in this title, granting to bonus of ([Skill x 2] + Luck)%.
Luck's bonus to Avoid is ([Attack Speed x 2] + (Luck)%.
Luck's bonus to Critical Evade is (Luck)%.
Luck also once again affects a single Skill in the Titles: Miracle.
Fire Emblem: Radiant Dawn
Luck remains exactly the same as it was in Path of Radiance, including effecting only the Miracle Skill. However the formulas for Hit Rate, Avoid, Critical Hits and Critical Evades do change due to other factors.
Fire Emblem: Shadow Dragon
Luck affects Hit Rate rate in this title, granting to bonus of (Skill + [Luck/2])%.
Luck's bonus to Avoid is (Attack Speed + [Luck/2])%.
Luck's bonus to Critical Evade is (Luck)%.
Fire Emblem: New Mystery of the Emblem
Luck affects Hit Rate and Critical Evade identically to Shadow Dragon.
Luck's bonus to Avoid is (Speed + [Luck/2])%.
Fire Emblem Awakening
Luck affects Hit Rate similarly to the Nintendo DS titles, ([Skill x 1.5] + [Luck/2]).
Luck's bonus to Avoid is ([Speed x 1.5] + [Luck/2]).
Luck's bonus to Critical Evade is (Luck)%.
Luck also now affects multiple skills within the game: Despoil, Armsthrift, and Miracle.
Fire Emblem Fates
Luck affects Hit Rate differently from previous titles, as Fates introduced two formulas for hit rates: One for Weapons and one for Staves, with Luck only affecting the Hit Rate of the former ([Skill x 1.5 + [Luck/2]).
Luck's bonus to Avoid is ([Speed x 1.5 + [Luck/2]).
Luck's bonus to Critical Evade is (Luck/2)%.
Luck is used by a handful of Skills in Fates: Dragon Ward, Salvage Blow, Miracle, Profiteer, Good Fortune, and Witch's Brew. As well as a few Personal Skills: Prayer of Bonds, Collector, Goody Basket, and Make a Killing.
Fire Emblem Echoes: Shadows of Valentia
Three Houses once again brings back the split between Magical Attacks and Physical Attack, with Luck only boosting your Hit Rate with Magical Attacks ([Skill + Luck]/2)%.
Luck's Bonus to Critical Hit Rate is ([Skill + Luck)/2]%.
Luck's bonus to Magical Avoid is ([Speed + Luck]/2)%.
Luck's bonus to Critical Evade is (Luck/2)%.
Luck once again affects a single Skill in this title: Miracle.
Fire Emblem: Three Houses
Three Houses keeps the split between Magical Attacks and Physical Attacks, with luck only boosting your Hit Rate with Magical Attacks ([Dexterity + Luck]/2)%.
Luck's bonus to Magical Avoid is ([Speed + Luck]/2)%.
Luck's bonus to Critical Evade is (Luck)%.
Luck is also used once again by a single skill in this title: Miracle. It does however affect one Personal Skill as well: Goody Basket.
Fire Emblem Engage
Luck no longer provides a bonus to Critical Hit Rate in this title.
Engage Splits Hit Rate into three different types depending on the whether a Weapon, Staff, or Cannonball is being used, with Luck effecting all three in terms or Hit Rate and Avoid.
Luck's bonus to Weapon Hit Rate is ([Dexterity x 2] + [Luck/2])%.
Luck's bonus to Cannonball Hit Rate is ([Strength + Dexterity + Build] + (Luck/2)]%.
Luck's bonus to Weapon Avoid is ([Speed x 2] + [Luck/2])%.
Luck's bonus to Staff Avoid is ([Resistance x 1.5] + ([Luck/2])%.
Luck's bonus to Critical Avoid is (Luck)%.
Luck is used by a handful of Skills in Engage: Divine Pulse, Lost & Found, Windsweep, Miracle. As well as one Personal Skill: Seconds?
Trivia
- In Fire Emblem Fates, Arthur has the lowest Luck growth out of any character in the entire game at 10%. It is further lowered to 5% in one of the potential promotions of his default class, Berserker. This is a reference to his character having notoriously bad luck in the story and in all of his supports.