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