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