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