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