as of 1/3/21 not gotten this achievement yet. Others have. Noticed there was no guide so in hopes of helping anyone out I will leave this up until then.You get this achievement for defeating the Act 3 boss ' Awakened One '.
You can defeat him with any character.
You cannot do this in custom. (achievements don't unlock in custom)
The Awakened has 2 Phases each with 300 HP
"Kill the Cultists as soon as possible as they get Stronger each turn after the first. The Awakened One itself is straightforward to handle: match your defense to the specific attack and use the rest of your energy to deal damage. Once you lower it to 0 HP, it will become invulnerable until its next turn while removing debuffs like weakened and vulnerable. Use that turn to ramp up your defense and possibly play power cards that were saved, since The Awakened One will immediately use its Dark Echo attack. Surviving Phase 2 is mostly a matter of surviving Dark Echo -- especially the first one, which could catch unsuspecting characters off-guard. Save any exhaust cards that will help speed up this phase (e.g. Terror).
Watch out for Phase 1's Curiosity ability. Whenever you play a Power, the Awakened One will gain 1 Strength Strength This is especially dangerous with the Soul Strike attack, which will use Strength bonus four times. Even if you have a Power build, you might want to avoid using them during this phase. Curiosity goes away in Phase 2, so you might want to spam your Powers when the Awakened One enters its invulnerable state between the phases, or as soon as Phase 2 begins.
Use temporary Strength debuffs (like Piercing Wail) right before killing his first form. The debuff will permanently lower Strength and carry on in Phase 2, "
Source for this and all bosses AND the strategy outlined above (edited by me to be more concise) https://slay-the-spire.fandom.com/wiki/Awakened_One
I HIGHLY RECOMMEND the slaythespire wiki for the helpful community, tips and just definition of abilities.
PLEASE PLEASE to help everyone else and brag -post your card combos that killed him/relics to help us strategize.
additional combos I have compiled no author: