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