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