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