Darkest Dungeon

I did stumble upon a neat "trick" to unlocking this particular achievement, though.

Later in the game there will be a boss named the Shrieker that appears via a town event. He will either steal your trinkets and you can hunt him down (A Thief in the Night event), or the townspeople mention his location and you can hunt him down (Shrieker's Prize event).

A couple of neat things about this boss;

- Doing these missions take you directly to the boss fight - no dungeon shenanigans are involved whatsoever.
- The boss flees after 4 turns and your party "wins" whether they kill him or not.

Knowing the above I figured I'd try sending only one person to the fight and attempting to survive with just them for the full four turns. It surprisingly went very smoothly and the achievement unlocked at the results screen.

I didn't "defeat" anyone or technically kill a boss - I just survived the 4 rounds until they ran away.

This was against a Champion level horrid Shrieker.

I sent a LVL6 Flagellant - fully decked out in max gear and skills. His dodge rate was decently high and I figured that his massive self-heal skills (Exsanguinate) would help out (as they did).

I sent him with the following two relics; Eternity's Collar and Martyr's Seal. My thought process was that they would help him survive Death's Door. Between dodges and Exsanguinate heals, though, it wasn't even needed.

Earlier in the game I sacrificed 3 guys in the Swine Prince fight and killed that boss with only one living character, but it didn't unlock for me there. (A lot of achievements are finicky in this game).