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 miracles.
Acquire all pyromancies.
Acquire all rings.
Acquire all sorceries.
Learn all gestures.
Reach "The Usurpation of Fire" ending.
Perform all forms of infusion.
Reach "To Link the First Flame" ending.
Reinforce a bonfire to the highest level.
Discover Blade of the Darkmoon covenant.
Discover Warrior of Sunlight covenant.
Discover Aldrich Faithful covenant.
Discover Mound-makers covenant.
Reach "The End of Fire" ending.
Defeat Nameless King.
Reinforce any weapon to the highest level.
Reinforce the Estus Flask to the highest level.
Defeat Ancient Wyvern.
Reach Archdragon Peak.
Defeat Lothric, Younger Prince, Lord of Cinder.
Defeat Dragonslayer Armour.
Defeat Champion Gundyr.
Reach the Untended Graves.
Defeat Oceiros, the Consumed King.
Defeat Dancer of the Boreal Valley.
Defeat Aldrich, Devourer of Gods, Lord of Cinder.
Defeat Yhorm the Giant, Lord of Cinder.
Defeat Pontiff Sulyvahn.
Defeat Old Demon King.
Discover Rosaria's Fingers covenant.
Defeat High Lord Wolnir.
Defeat the Deacons of the Deep.
Defeat the Abyss Watchers, Lords of Cinder.
Discover Watchdogs of Farron covenant.
Defeat Crystal Sage.
Discover Blue Sentinels covenant.
Defeat the Curse-rotted Greatwood.
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.