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