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