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