Call of Duty: Black Ops 4

So, first of all, obviously you want to get the Death of Orion as soon as possible, if you don't know how to get it, there are guides available for it. You should be able to do this in a solo match by around round 10. Once you get it, I recommend getting enough to pack-a-punch it because this weapon does have a high chance to make crawlers if not hit accurately so upgrading it will help reduce that chance.

Once it is upgraded to Serqet's Kiss, start training zombies down in the pack-a-punch room. Once you have a horde of around 20 zombies, you're going to want to either run under the stairs (if there is fire going on you can also run through the busted doors in PaP room) and get through the arch so the zombies get super tight. Try to hit the highest cluster of zombies without charging your Serqet's Kiss.

It took me about two or three attempts and I got the achievement fairly easily. Try to do it on as low a round as possible to prevent crawlers because if they don't die, it won't count. Best of luck!

Feel free to watch my video on how to unlock the "Death Of Orion" weapon,

Once you have it you want to Pack-A-Punch it first turning it into the Serket's Kiss.

Then you want to round up a bunch of regular zombies inside the TEMPLE (killing the guardians so they don't get in your way) and once you feel you have a big enough pack following you then go to one of the 2 doorways that open when you unlock the PaP.

When you do, turn around and wait for your pack of zombies to line up for you and take your shot. Make sure to just TAP and don't HOLD it. Hopefully you get enough in the one shot for the achievement, good luck!

All of my Call Of Duty: Black Ops 4 HD Achievement Guides can be found here! :) (Mobile Friendly)
https://www.bradleafsfan9.com/call-of-duty-black-ops-4

Okay so this guide is to help those with a 'Death of Orion' which must first be obtained to obtain this achievement.

Pack-A-Punching the wonder weapon to a 'Serket's Kiss' voided the achievement and I could not unlock it with this weapon. I also could not seem to kill 9 zombies with a single UNCHARGED shot no matter if the round was low or high but the first time I tried this with insta-kill on I got it.

The accompanying video was created by myself and shows me using the 'Death of Orion' (note that it IS NOT Pack-A-Punched) and training zombies in the starting arena till I finally got the achievement. You won't see the achievement pop as the video was made using the in-game recording and please note that the action unlocking the achievement was the shot at 0:20, but did not unlock until a few seconds later which is coincidentally after I shot a second time.

This took me 4-5 rounds of training in the spawn arena and trying to kill 9 with a single uncharged shot as the elemental zombies and gladiators kept making this difficult but like I previously mentioned. The insta-kill powerup made this work instantly. Hope this helps:

I managed to pop this achievement with the first shot from my Death of Orion.

I do not recommend doing the easter egg in order to obtain the Death of Orion (It is a real hassle). I found the quickest way to obtain the gun was by opening random weapon boxes.

Start the game off by completing the banner challenges in the middle of the map until you receive the pack a punched pistol. Next, you need to start saving up your points as you go around each god temple completing the gongs in order to obtain the heads to open pack a punch. By this point, you may have been fortunate enough to pick up the Death of Orion from the random weapon box, however, if you haven't, continue saving up points to spend on opening the box.

Once you have obtained The Death of Orion, pack a punch it as it becomes more powerful. I also highly recommend getting your hands on the homunculus grenades (Monkey bombs). You now have everything you need to complete this achievement.

I found the best way to unlock it was to run around the center of the map on a round when the flames were not there. Once you have accumulated a large horde of zombies, throw a homunculus grenade from the center of the map into one of the god temples. The horde of zombies will all start running into the temple, giving you a nice amount of time to line up a shot and pop the achievement. You do not require the homunculus grenades, however, it gives you a lot more time to line up your shot as the zombies are focusing on something else.