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