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