West of Dead

To obtain this achievement you must complete the true ending of the game

First you need to do the following:

1. Beat the game at least one time (Reach Chapter 4)
2. Start a new run
3. Find the three blue souls (white ones don't count) during an unique run. If you die, you need to start over again. (They are guaranteed to appear, but they spawn in random locations, always on checkpoint marks, and only on the main zones of the game (Crypt, The hunt, Mines, Farm, Town, Church) They can appear on every zone of the game. This souls ask you for help, if you accept they will drop a "Memory" needed to "destroy" the final boss. Also they will "burden" you their sins which means you need to kill 6 enemies without reciving damage. If you get hit you are dead. The game is super bugged at the moment, in my personal experience, sometimes the souls didn't count towards the true ending and I had to start over again. If Mason says something like "I feel the presence of a friend/deputy/familiar/posse member in here" means that a blue soul it's within that zone.
4. If you did correctly the 3rd step, now you will see the final zone (where you fight the final boss) with 3 blue pillars that you need to take down. If you do this and kill the final boss you get the achievement.

There is also some "Lore" memories that you get from white/gold souls and sometimes outlaws but You don't need to obtain any of those to banish Injustice I tested myself doing the true ending on another account.

After completing the main game, beating the preacher 3 times, you will start chapter 4.
This achievement is hard af imo but I would like to share some tips on how I eventually got this.
I want to mention unless you are a god you will not get this on your first try or even your 10th. It will take you dozens of runs and some luck of course because of the genre.

The premise of the achievement is to find, speak to and accept the burdens of 3 blue souls throughout your run. Locations are random but they always spawn at checkpoints and sometimes they spawned at the checkpoints after defeating an outlaw. If you die during the game you will have to start a new run. Once you've done that you will have to make it to the third encounter of the Preacher because the 1st and 2nd encounters will be replaced with Outlaws.

Once you've made it to Preacher III you have to shoot three blue pillars knocking them down, they will obstruct some of the map and the Preacher. Don't forget to shoot them down because if you don't and you kill the preacher it won't count. Best way is to have a long range gun and shoot the first visible pillar before you step into the entrance of the fight.

Now for tips on the boss fight:
It's best to have a long range weapon, shotgun, shield and a thowable(dynamite,plague bomb) upgraded health flask to large. Throwable is for the skulls he throws out but you can use it on the boss as well. Now you can skip the skull phase if you have a certain weapon called bombadier which is a very powerful weapon.
Weapons I preferred to use: Bombadier, Workhorse,Longshot, blaster.
Pretty simple mechanics to defeat him: shoot at his feet once you down him there will be a shockwave and he is vulnerable throw everything you got at him. He will get back up again rinse and repeat.

Boss abilities:
1. He will throw fireballs, or souls if you will, at you just try to get far away from him and stay in cover before he does the animation. If you do it correctly the balls will hit the cover and destroy the cover.
2. He will throw out 6 skulls, they will each attack you again with mini fireballs while following you. Move cover to cover but kill them quick with your shotgun or throwable because they will follow you behind cover.
3. Falling rocks, red circles will show on the ground, dodge before they hit you.
4. Shockwave, he will do this everytime you down him, dodge towards him just before the yellow shockwave hits you. In his last phase this is all he will do.

Now onto maps:
1st map is crypts, run through map, get your 2 upgrades, I usually upgrade perception twice.
2nd map the Hunt, another run through but be careful of the exploding lanterns that run towards you, a shotgun is great for them. Also butcher guy starts to show up and throws hatchets. Upgrade Perception again 3 or 4 times on this map.
3rd map mines, more lantern guys and boulder or rock enemies, you can see the light in the ground so be careful not to get too close to them but they're pretty slow so you can dodge them if needed. Also dodge over the sort of yellow lines in the map if necessary to get to the next area. Start to upgrade toughness to level 3.
4th map is the farm, lantern guys again, dogs and trappers who will stun you if you fall into their traps.
5th map is the town, this is where the bombadier gun is really helpful as the enemies like to bunch up near the healer or priest if you damage them too much. Also avoid the gunners that show up in the windows, they don't damage you much but if you have a burden you will get one shot. Your perception should atleast be level 7 by the end of this map, toughness 5 or 6.
6th map is the annoying af church. Hopefully you have all the blue souls before this map because the enemies can be overwhelming. You have one guy that likes to teleport behind you and shoot you in the back. You have big boy that throws fireballs which you have to dodge perfectly seemingly and priests that heal. I usually run through each section collecting the upgrades and weapons I need before leaving and avoiding all enemies. My toughness and Perception was at 9, resourcefulness is not really useful.

If there's anything I missed that you would like to know I'd be glad to answer.

As the other guides mentioned, this is once you have beaten the Preacher twice and Injustice once to get to chapter 4.

This achievement requires you to find three blue lost souls, accepting their burdens and making it to Injustice at the end, destroying three pillars before you kill him.

Now, I had to dig around in comments to figure out the blue lost souls and it looks like I am not the only one, so hopefully this helps.

1. Blue Lost Souls

- Wanted posters at the beginning of the run will tell you the location of blue souls on Chapter 4. Press on each poster next to the guy in a chair by a door
- If a blue soul is not in the area he says, quit out of the game and restart. It probably glitched.
- Try and do it on a run with easy levels, like Crypt and Hunt instead of ones like Canyon and Churchyard

2. Equipment Setup

- Lantern and Shield are good, I also used throwables for the boss since lanterns don't work.
- I like pistols and revolvers since they have good range and hit more often than rifle. I personally recommend Traitor, Deadshot, or Fifth Time Lucky. Deadshot will wreck the final boss.
- Use the defender charm that gives you health
- Make sure you evenly level up your attack damage and your health, prioritizing damage.

3. The Boss Fight

If you made it this far the pillars around the room should be blue. You should be able to take down one pillar without even entering the boss room.

- Take out one or two pillars before entering the boss room
- Shoot his feet with one gun and then use the Deadshot to shoot him in the head when he is staggered
- Kill the pillars as you move past them, try not to circle the room too many times
- I recommend getting the bosses health low, going after the remaining pillars, and then finishing the boss