Here is the full list of all 43 DARK SOULS III achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Complete all achievements.
Acquire all rings.
Acquire all miracles.
Acquire all pyromancies.
Reach "To Link the First Flame" ending.
Reach "The Usurpation of Fire" ending.
Reach "The End of Fire" ending.
Reinforce the Estus Flask to the highest level.
Acquire all sorceries.
Perform all forms of infusion.
Learn all gestures.
Defeat Lothric, Younger Prince, Lord of Cinder.
Discover Blade of the Darkmoon covenant.
Discover Mound-makers covenant.
Reinforce a bonfire to the highest level.
Defeat Dragonslayer Armour.
Defeat Yhorm the Giant, Lord of Cinder.
Defeat Nameless King.
Reinforce any weapon to the highest level.
Defeat Ancient Wyvern.
Reach Archdragon Peak.
Defeat Champion Gundyr.
Reach the Untended Graves.
Defeat Oceiros, the Consumed King.
Defeat Aldrich, Devourer of Gods, Lord of Cinder.
Discover Aldrich Faithful covenant.
Defeat Pontiff Sulyvahn.
Defeat High Lord Wolnir.
Defeat Old Demon King.
Defeat Dancer of the Boreal Valley.
Discover Rosaria's Fingers covenant.
Defeat the Abyss Watchers, Lords of Cinder.
Discover Watchdogs of Farron covenant.
Defeat the Deacons of the Deep.
Defeat Crystal Sage.
Discover Blue Sentinels covenant.
Defeat the Curse-rotted Greatwood.
Discover Warrior of Sunlight covenant.
Defeat Vordt of the Boreal Valley.
Discover Way of Blue covenant.
Become a Host of Embers for the first time.
Defeat Iudex Gundyr.
Light a bonfire flame for the first time.