Bountiful Harvest

Easy Solo Achievement for Level 70 Dragonflight & Beyond...

1) Mythic Difficulty.

2) Achievement can be tracked, when requirements are met it will turn from Red to White.

3) Head up the stairs to the boss area, then run past him all the way to the Grisly Curio sparkly item located in the far corner, as revealed here: https://imgur.com/8viAILz

4) Kill the Grisly Colossus.

5) Pull boss, and drag boss to the corpse of the Grisly Colossus.

6) Eventually boss will use Final Harvest on the corpse.

7) Kill boss.

8) ?

9) Profit. Achievement Completed.

Full credit to Linodas' group for all their fantastic work! Wanted to clarify a few things about the achieve.

The Grisly Curio is in the plants on the far side of room, opposite where you enter Amarth's encounter area. It does respawn when the boss does. You can use the Curio and get the mob low before engaging the boss. You may also be able to kill the add entirely before engaging the boss, but we elected to drop it to 5% then pull.

After killing the first wave of adds the boss will cast Bountiful Harvest. As long as he's near the add's body he'll consume it and get the Final Harvest debuff. When he consumes the add's body he heals to full health and gains a buff that restores 1% of his max health every 4 seconds. This was our first Mythic dungeon and we were all around 130-140 Ilvl which made it very difficult to both get the adds down and still keep up with his heal but in more gear it should be a breeze.

Once he has the debuff you can kill him.

Edit (11/30/20): Don't forget if you have Kyrians in your group you can grab one of the Javelins on the way to boss and give him a damage taken increase. There are two javelins on the way to him and they're here.

FrostyShot#1667 is my btag (US Servers) if you have questions.

All the responses here are accurate, but incomplete.

Once the boss casts his first Final Harvest the achievement, and the fight, actually begins because the boss heals to full. By this time, the boss will already have six stacks of Tortured Echoes (the buff that does group-wide constant damage). Additionally, the boss does 25% more Shadow damage. His Necrotic Breath now hits harder, his Necrotic Bolts hit harder, and his constantly growing AoE aura hits harder too. In addition to healing 1% health every 4 seconds, all of his adds also continuously regain health.

This puts a serious amount of strain for DPS uptime on the boss while adequately finishing off the adds before the Final Harvest instantly wipes your group. Because the boss now does 25% more damage and already starts with an empowered Tortured Echoes, your healer will also have to deal with progressively more and more damage if your DPS is struggling to eat through the regeneration.

This will only get easier with time, but if you're attempting this on week one of the expansion, this might be the hardest achievement to complete, as it is literally the only achievement where lack of gear plays a factor. Every other achievement in the meta is just a matter of proper execution, playing skillfully, or simply taking your time. If your DPS is slow and your healer is struggling, then you may have to get creative, such as using the Javelins and restarting the instance if you wipe.

The only tips I can give if you are struggling are to possibly tank the boss nearer to a wall to reduce the valid play-space for adds to spawn, with the hopes that they stack immediately grouped up instead of risking having mages/crossbowman incredibly far apart. East of where you pull the boss the room converges in a V-shape dramatically localizing the spawn space to a cone. Be extremely careful tanking him too closely to the wall as dodging the breath will become impossible if he's actually against the wall. I found simply hard-focusing the adds gave us more uptime on the boss instead of hoping cleave would suffice when all you're really doing is just reducing your effective boss damage while allowing the adds to heal for even longer. Having a single DPS hard-focus the boss full time might also be optimal if their DPS collapses too much from heavy movement or target swapping. Experiment a bit to find what works for you and make sure you map out your AoE DPS cooldowns to make managing the adds more straightforward. Even with all these items, we still had to stretch ourselves to complete the achievement and it took us quite a few pulls. Good luck.