Jack Was Here



In your search for Jack, you'll come across Jack's slingshot and picking it up will unlock this achievement. This can't be missed.

Nothing But Make Believe
Missable


As Philip, you'll have to prove to yourself that a familiar statue isn't performing miracles. To do this you'll have to do most of these actions (it will unlock before you do all of these):
Question the Priest when you have the chance to

• Talk to Jonathan (3x)
  
• Talk to Remigius (3x)
  
• Talk to the monks (2x)
  
• Talk to Jaggler (2x)
  
• Talk to Martha
  
• Examine the "strange animals"
  
• Examine the cloth in the back of the cart

Do not talk to the boy in the back of the cart before unlocking this achievement. The game will continue and autosave if you do.

A Cry For Help
Missable


Make sure to help the girl (Elizabeth) before going into the building (might not be needed, but won't hurt). Once you get outside, don't make her talk before taking care of her:

• Give her a blanket (it'll be between the fire and the door)
  
• Give her some soup

She will automatically open up to you and this achievement will unlock.

Self Defense
Missable


Before this scene ends, Elizabeth is going to be collected and will have to leave. Before she has to, you'll have a chance to do one thing for her. Give her your dagger and this achievement will unlock.

Brother Marcus
Missable


Oh boy, this achievement is based on a decision you made way back in Book 1, Chapter 1. This is only achievable if you turned in Brother Marcus for stealing Cuthbert's keys and food to Remigus. You will get this achievement when you investigate the kitchen.

If you didn't turn in Marcus, you will have to go all the way back to the beginning.

Vox Populi
Missable


When talking about dealing with the Hamleighs, choose to ally with the outlaws. You'll be sent around to find someone called "The Butcher" and once you do, you have to choose your words carefully. These dialogue choices will guarantee you to get them on your side and this achievement:

• Lead them
  
• Stress you were poor once, too
  
• Mention how your father was a just earl
  
• Mention Philip's support

The Oath



This is unlocked when William is no more and the coat of arms you made in Book 2 is raised.
Not missable to my knowledge

Countess
Missable


In Book 2, you'll need to support Richard, but not too much (if that makes sense). You can't hesitate when taking the oath and you need to take charge. Then after the timeskip, I supported Richard in the game that you have to play to get the achievement Team Player and gave him the same money I gave Philip. In Book 3, after the Oath is fulfilled, answer "Thank you, brother" when he says that he wants you to become Countess.

However, if Richard died in Book 2 you will get this achievement by default.

The Truth Revealed



During Philip's trial, the whole conspiracy behind Jack's father's death will be revealed in your search for a witness.
This doesn't seem missable, but just in case I choose to have Jack accuse Waleran, say his name was "Jack Jackson", and showed the chalice.

You'll just have the achivement for finishing the whole game left!