Here is the full list of all 38 Dark Souls II achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Earn all achievements
Learn all pyromancies
Learn all miracles
Inherit Benhart of Jugo's equipment
Learn all sorceries
Inherit equipment from Lucatiel of Mirrah
Learn all hexes
Defeat Vendrick
Learn all gestures
Inherit Captain Drummond's equipment
Discover the abysmal covenant
Discover an ancient covenant
Increase the population of Majula
Inherit equipment from the head of Vengarl
Inherit Steady Hand McDuff's equipment
Discover the covenant of the protectors
Discover the covenant of the fittest
Inherit Laddersmith Gilligan's equipment
Light all flames on the map in Majula
See the ending
Max-out devotion to covenant
Acquire Ashen Mist Heart
Reinforce a weapon to its limit
Acquire the King's Ring
Defeat Looking Glass Knight
Light the primal bonfire in Brightstone Cove Tseldora
Discover the covenant of the bloodthirsty
Light the primal bonfire in the Iron Keep
Discover a most brilliant covenant
Light the primal bonfire in the Black Gulch
Discover the covenant of rodents
Give Rosabeth of Melfia something to wear
Light the primal bonfire in Sinner's Rise
Discover the clangorous covenant
Defeat the Last Giant
Discover the covenant of the meek
Die for the first time
Reclaim flesh and set out as an Undead