In Fire Emblem Heroes, it appears as a type A passive skill which can be learned without inheriting by: Alfonse, Camilla (Tropical Beauty, Celica (Warrior Priestess), Eliwood (Blazing Knight), Dimitri, Delthea, Effie, Elincia, Hawkeye, Klein*, Reinhardt (Thunder's Sword), Roy (Youthful Gifts), Siegbert and Ursula. Of these; only Celica (Warrior Priestess), Eliwood (Blazing Knight), and Dimitri have Death Blow 4 by default.
Combined with high critical weapons, users with Killer weapons (also including the Barb Shuriken, Mjölnir, Odin's Grimoire, Beruka's Axe and the Great Club) can deal extremely high damage. It is best combined with high damage-boosting skills like Rend Heaven (to the applying stat), as it will almost always guarantee a one-hit strike if the target does not have any sort of Miracle protection on them. It is best combined with other factors (e.g Berserker provides additional critical bonus) to further increase the damage dealt in a critical hit.
However, most critical dealing weapons have low accuracy (and usually come with other penalties), so ensure that your units have high hit rates, as a chance to hit is rolled before the critical hit chance.
In Heroes, it affects the damage dealt rather than crit chance, but only when the unit initiates combat.
In Three Houses, it increases the Str of the unit by 6 during combat, if they initiate combat.
|Effects||When user triggers the battle, Critical rate +20|
|Notes||Learned by Oni Chieftain at Level 5 or higher.|
|Death Blow 1||Upon initiating combat.||50|
|Effects||Grants Atk+2 if unit initiates combat.|
|Death Blow 2||Upon initiating combat.||100|
|Effects||Grants Atk+4 if unit initiates combat.|
|Death Blow 3||Upon initiating combat.||200|
|Effects||Grants Atk+6 if unit initiates combat.|
|Death Blow 4||Upon initiating combat.||300|
|Effects||Grants Atk+8 if unit initiates combat.|
|Death Blow||Upon initiating combat.||-|
|Effects||If unit initiates combat, grants Str +6 during combat.|
|Notes||Learned by mastering the Brigand class.|