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