Achilles: Legends Untold

This achievement requires that you have the full status effects of poison, curse, bleed, and burn active on your character at the same time, and then kill an enemy. The trick to this is first acquiring the curse status. This status is permanent until you either remove it with an item or use a shrine. The cultist enemies late in the game (specifically in the Battleground of Fear) can inflict this on you, so let them hit you a few times until you see your health bar get reduced and notice your character moving more slowly.
 

Now, equip your character with both poison and fire petards and head somewhere with lions or wolves and let them attack you a few times to receive the bleed status (the lions near the Dead River shrine are great for this). Now you've got 2/4 statuses and can inflict the final two yourself by throwing a petard of each type at your feet and standing in the fire and poison clouds. Once you have all four statuses actively damaging you, quickly kill an enemy before you die from all the damage over time you're taking from them. Chug a health potion if needed, but if you're in NG+ this should be no issue with all the vitality upgrades you've probably got by then.