Here is the full list of all 25 The Fifth Horseman achievements.
Start the game with 9 strength points.
Start the game with 9 endurance points.
Start the game with 9 dexterity points.
Start the game with 9 wisdom points.
Start your first game.
Die for the first time.
Win the fight against the Horseman of Famine.
Win the fight against the Horseman of Pestilence.
Win the fight against the Horseman of War.
Win the fight against the Horseman of Death.
Complete the Golden Crown event.
Complete The Rescue event.
Achieve the Pure status.
Achieve the Bane status.
Kill the old lady in the castle.
Finish the game for the first time.
Read the mysterious letter.
You've seen the first ending.
You've seen the second ending.
You've seen the third ending.
You've seen the fourth ending.
Have 14 or more strength points.
Have 14 or more endurance points.
Have 14 or more dexterity points.
Have 14 or more wisdom points.