For those Destiny 2 players whom are still trying to get the exotic Shotgun the Fourth Horseman here are the most simple steps to finish the quest and get the gun.
The first step is to talk to Zavala and pick up the quest. He will send you to find his office in the Tower. To find his office watch the video below.
After watching the video and getting to his office you will notice the Fourth Horseman isn’t there.
For step two head back to Zavala to inform him about the breach in security. After talking to Zavala players go to Mars to talk to Ana Bray. She will set you up with a new quest to find intel on the Cabal. You will have to kill Cabal and complete Public Events to gain intel on the Cabal. Once you’ve collected enough intel you return to Ana.
I highly recommend doing the Escalatioin Protocol on Mars you earn 10% per round. In other words you’ll get done with that quest faster.
Once you’re done getting intel she wants you to kill Psions and open Cabal planetary chests. Recommend doing the Lost sector “Ma’adin Subterrance” in the Glacial Drift about four times since there is tons of Psions there.
Step three, once completed all of Ana’s quests you go back to the Tower to speak to Benedict 99-40 in the Annex. He will reply a message from Emperor Calus. He wants you to eliminate encryption signals in EDZ, so head to Earth and defeat enemies, do patrols, or complete public events. After completing that head back to the Tower and report back to Benedict 99-40. He will give you a new quest to complete the Legendary Lost Sector, The Quarry.
With that comes step four, before you can start the legendary Lost Sector quest you first have to complete the EDZ daily bunker but, there’s a downfall. After clearing out the bunker it’s a 50/50 chance you my or may not get the right quest because it changes everyday.
After unlocking and getting the Legendary Qurry Lost Sector mission you have to defeat all the enemies and the recommended power level is 1000 but you don’t have to be. As long as you have a good set up and is at least in the 970’s or higher.
The final step, step five. Which is pretty short step actually. While doing to legendary Quarry Lost Sector mission you have to kill all the enemies but, once you get to the last one all you have to do is defeat the small enemies and the main boss. Now there’s going to be 3 big enemies left after taking out the little ones. The two enemies that heal themselves are NOT important. You have to kill the one that doesn’t regenerate its health, that’s the main boss the other two are just its body guards. After defeating the main last boss the other two disappear and you open the chest at the end and bam you get the Fourth Horseman!
A/N: There is originally 10 steps but I put some together to shorten it! I hope this helps out any guardians having any problems!