Warhammer 40,000: Inquisitor - Martyr

Massacre bonuses are granted for completing specific feats during combat.

The "Angel of Death" bonus is awarded by getting three critical hits with no more than three seconds between each one.

This should pop easily through normally playing the game after a
time but to make it easier you can invest in the critical hit skill tree or equip any gear that increases critical hit chance. Remeber the more frequently you hit the more likely you are to crit regardless so any fast firing weapon or area of effect attack will increase crit likelihood also.

ThaDevilzHand adds -
9/9/2021 - "There was an update today, and it seems like they must have reverted the requirements to what it was previously. I had to resort to the tactics in this guide to get the achievement, as it never really popped naturally by just playing. However, after todays update I'm getting them left and right without actually trying"

If this is indeed true then the following information is some what outdated but should still help pop the achievement.



Critical chance caps at 50%
Supreme Critical chance caps at 50%
You'll pretty much need a full 100% although I did get away with having 97% a few times.
I used the ranger...assassin whatever class. (I forget what she's called)
I wouldn't recommend any other class for this achievement.
I don't remember my build but I did use the grav-gun and pretty much every perk/upgrade that involved crit


The digital weapons skill is handy but it only counts as normal crit chance. Regardless of the 30% it gives you, it won't exceed the 50% cap.

Edit:
AllOvaMyself adds:

Assassin Class

"So to elaborate on Laserbeam's solution, I'll give you the gear, perks and all that I've got:

Character

Attributes:
Work toward maxing Bloodlust to 25 - You'll get +5% Supreme Crit Chance and Crit Strength for 5 seconds on kill. Also keep in mind I do not have this yet and still managed to get it to proc, so it will only make things easier, I'm sure.

Perks:
Frenzon Dispenser - +10% Crit Chance/-10% Max Health
Keen Fury - +1% Supreme Crit Chance and +1 Crit Strength for 5 seconds on kill, stacks 10 times
Stagger Exploitment - +5% Supreme Crit Chance and +10 Critical Hit Strength against debuffed enemies

At level 59 you'll unlock Designated Marksman which has for all ranged weapons +5% Supreme Crit Chance, +5 Crit Hit Strength and +15% damage bonus and tighter shot spread (shot spread is irrelevant with a Grav-Gun). I do not have this yet and will likely swap it in for Stagger Exploitment for a more guaranteed buff.

Inventory

Gear:

Obviously anything with Crit Chance is ideal. My gear has other enchants, I'm just listing the Crit Chance stuff or we'd be here all day.

Eye implant (purple) - +3.8% Critical Chance
Digital Weapons (relic) - for the Crit Chance boost
Hololithic Armour (purple) - I have slotted the Psalms Iron and Binharic. Iron gives 1% Supreme Crit Chance for 2 seconds on kill and Binharic doubles the effect duration.
Inoculator (green) - if you have a Yellow or Multi-Colored Slot, you can put in the Frenzon Component which gives 10% Supreme Crit Chance and +40 Crit Strength for 5 seconds on use of the Inoculator - if you can slot multiple, even better. Pop this along with Digital Weapons. I also have another Iron Psalm slotted into it.
Grav-Gun (Archeotech Relic) - +7.3% Crit Chance
Signum (green) - +3.4% Crit Chance

Passives

Ranged Combat:
Starting in the upper right, there are 4 +1% Crit Chance nodes you can unlock.

Single DPS:
Starting in the upper left, go down 3 spaces to find Cortical Pumps which has +5% Crit Chance for Single Target skills for the first hit on an enemy. Grav-Gun basic attack is Single Target.

Critical Hits:
Max this out.

Suppression:
Top middle is Natural Predator which gives +2% Crit Chance when Suppression status is Protected (green).

My Critical Hit Chance Base is 45% standing still but I use the Digital Weapons and Inoculator together to get those boosts. You should be able to buff yourself and charge large groups with just the basic A attack.

Hope this helps."